# Letter frequency

(Redirected from Count letters)
You are encouraged to solve this task according to the task description, using any language you may know.

Open a text file and count the occurrences of each letter.

Some of these programs count all characters (including punctuation), but some only count letters A to Z.

## 11l

Translation of: Python
```F countletters(s)
DefaultDict[Char, Int] results
L(char) s
V c = char.lowercase()
I c C ‘a’..‘z’
results[c]++
R results

:start:
print(letter‘=’count)```
Output:
```d=1
e=1
h=1
l=3
o=2
r=1
w=1
```

## 8080 Assembly

This program prints the frequency of each printable ASCII character contained in the file.

```bdos:		equ	5	; CP/M syscalls
putch:		equ	2	; Print a character
puts:		equ	9	; Print a string
fopen:		equ	15	; Open a file
fcb:		equ	5ch	; FCB for file given on command line
dma:		equ	80h	; Default DMA
org	100h	; CP/M loads the program starting at page 1
;; Zero out pages two and three (to keep a 16-bit counter
;; for each possible byte in the file).
;; We can do this because this program is small enough to
;; fit in page 1 in its entirety.
xra	a	; Zero A.
mov	b,a	; Zero B too (make it loop 256 times)
lxi	d,200h	; Start of page two
zero:		stax	d	; Zero out a byte (store A, which is zero)
inx	d	; Next byte
stax	d	; Zero out another byte
inx	d	; Next byte
dcr	b	; Decrement the loop counter.
jnz	zero	; Continue until B comes back to zero.
;; Open the file given on the command line.
lxi	d,fcb	; CP/M always tries to parse the command line,
mvi	c,fopen	; and gives us a file "object" in page zero.
call	bdos	; We can just call fopen on it.
inr	a	; It sets A=FF on error, so if incrementing A
jz	error	; rolls back over to 0, that's an error.
;; Process the file record by record.
;; In CP/M, each file consists of a number of 128-byte
;; records. An exact size is not kept.
;; If a text file is not an exact multiple of 128 bytes
;; long, the last record will contain a ^Z (26 decimal),
;; and anything after that byte should be ignored.
read:		lxi	d,fcb	; From the file control block (the "object"),
mvi	c,fread	; read one record. By default it ends up in
call	bdos	; the last half of page zero.
ana	a	; Zero carry flag.
rar		; Low bit says if end reached
jc	output	; If so, go print the table
ana	a	; If any other bits are set, that's a
;; Count the characters in the current record.
lxi	d,dma-1	; Set DE to point just before the record
byte:		inr	e	; Go to the next byte.
jz	read	; If end of record, go get next record.
ldax	d	; Grab the current byte
cpi	26	; If it is EOF, we're done.
jz	output	; Go print the table
mov	l,a	; Otherwise, increment the counter for this
mvi	h,2	; character: the low byte is kept in page 2.
inr	m	; 'm' means the value in memory at HL.
jnz	byte	; If no rollover, we're done; count next byte
inr	h	; But we're keeping a 16-bit counter, so
inr	m	; if there is rollover, increment high byte.
jmp	byte	; The high byte is in page 3 -unorthodox, but
; it's easy to access here.
;; We've done the whole file. For each printable
;; ASCII character (32..126), print the character and
;; the count.
output:		mvi	a,32	; Start at 32.
;; Print a character and its counter
char:		mov	l,a	; Load 16-bit counter into DE. Low byte
mvi	h,2	; is in page 2 at a;
mov	e,m
inr	h	; And the high byte is in page 3.
mov	d,m
mov	a,d	; Test if the counter is zero
ora	e
mov	a,l	; Put the character back in A
jz	next	; If zero, don't print anything.
push	psw	; If not, push the character,
push	d	; and the counter.
mvi	c,putch	; Print the current character
mov	e,a
call	bdos
lxi	d,separator	; Then print ': '
call 	outs
;; Then convert the counter to ASCII
pop	d 	; Retrieve the counter
lxi	h,numend	; Get pointer to end of digit string
push	h	; And put it on the stack
dgtloop:	xchg		; Put counter in HL (16-bit accumulator)
lxi	b,-10	; Dividend is 10
mov	d,b	; Start quotient at -1 (we'll loop once
mov	e,b	; too many, this corrects for it)
divloop:	inx	d	; Increment the quotient,
dad	b	; subtract 10 from the dividend,
jc	divloop	; and keep doing it until it goes negative
lxi	b,10+'0'	; Add 10 back to get the remainder,
dad	b		; plus '0' to make it ASCII.
mov	a,l
pop	h	; Retrieve digit pointer
dcx	h	; Decrement it (to point at current digit)
mov	m,a	; Store the digit
push	h	; And store the new pointer
mov	a,d	; Check if the quotient is now zero
ora	e
jnz	dgtloop	; If not, do the next digit.
pop	d	; Set DE to point at the first digit
call	outs	; And output it as a string.
pop	psw	; Restore the character
next:		inr	a	; Increment it
cpi	127	; Did we just do the last character?
jnz	char	; If not, go do the next character.
ret		; If so, we're done.
;; Print the error message
error:		lxi	d,errmsg
;; Print string
outs:		mvi	c,puts
jmp	bdos
;; Strings
errmsg:		db	'?\$'	; "Error message" (if file error)
separator:	db	': \$'	; Goes in between character and number
number:		db	'00000'	; Space to keep ASCII representation of
numend:		db	13,10,'\$'	; a 16-bit number, plus newline.```

## 8th

```needs map/iter

0 args "Give filename as param" thrownull
f:slurp >s s:len numtasks @ n:/ n:ceil 1 a:close s:/ a:len numtasks ! constant work

m:new constant result

: print-character-count  \ m s -- m
swap over m:@  rot   s:size 1 n:= over   -1 s:@ nip 31 n:<  and if
-1 s:@ nip "<%d>" s:strfmt
else
"'%s'" s:strfmt
then
"%s: %d\n" s:strfmt . ;

: print-results
tasks @ a:len ( a:pop t:result nip ( result -rot m:[]! drop ) m:each drop ) swap times drop
result ( nip array? if ' n:+ 0 a:reduce then ) m:map
m:keys ' s:cmp a:sort ' print-character-count m:iter drop ;

"" s:/ ' noop a:group
( nip a:len nip ) m:map ;

a:new

: app:main
print-results
bye ;```

## AArch64 Assembly

Works with: as version Raspberry Pi 3B version Buster 64 bits
or android 64 bits with application Termux
```/* ARM assembly AARCH64 Raspberry PI 3B */
/*  program cptletters64.s   */

/************************************/
/* Constantes                       */
/************************************/
/* for this file see task include a file in language AArch64 assembly*/
.include "../includeConstantesARM64.inc"
.equ BUFFERSIZE, 300000

/************************************/
/* Initialized data                 */
/************************************/
.data
szMessOpen:           .asciz "File open error.\n"
szMessStat:           .asciz "File information error.\n"
szMessClose:          .asciz "File close error.\n"
szMessDecryptText:    .asciz "Decrypted text :\n"
szMessCryptText:      .asciz "Encrypted text :\n"
szMessErrorChar:      .asciz "Character text not Ok!\n"
szFileName:           .asciz "unixdict.txt"
//szFileName:           .asciz "test1.txt"
szMessResult:         .asciz "Result:    = "
szCarriageReturn:     .asciz "\n"
szMessStart:          .asciz "Program 64 bits start.\n"
/************************************/
/* UnInitialized data               */
/************************************/
.bss
sZoneConv:            .skip 24
tabCptLetters:        .skip 8 * 52         // (A-Z a-z) counter array
sBuffer:              .skip BUFFERSIZE     // file buffer
/************************************/
/*  code section                    */
/************************************/
.text
.global main
main:                        // entry of program
bl affichageMess
mov x0,AT_FDCWD
mov x2,#O_RDWR           // flags
mov x3,#0                // mode
mov x8,#OPEN             // file open
svc 0
cmp x0,#0                // error ?
ble 99f
mov x9,x0                // FD save

mov x0,x9
ldr x2,#iBufferSize
svc 0
cmp x0,#0                // error read ?
blt 97f
mov x6,x0                // file size
mov x0,x9
mov x8,#CLOSE            // call system close file
svc 0
cmp x0,#0                // error close ?
blt 96f
mov x1,x6
bl cptLetters

b 100f
96:
bl affichageMess
mov x0,#-1               // error
b 100f
97:
bl affichageMess
mov x0,#-1               // error
b 100f
99:
bl  affichageMess
mov x0,#-1               // error

100:                         // standard end of the program
mov x0, #0               // return code
mov x8, #EXIT            // request to exit program
svc 0                    // perform the system call

/***************************************************/
/*   letters frequency                   */
/***************************************************/
/* r0 contains a file buffer */
/* r1 contains string length */
cptLetters:
stp x1,lr,[sp,-16]!
stp x2,x3,[sp,-16]!
stp x4,x5,[sp,-16]!
stp x6,x7,[sp,-16]!
mov x3,#0              // index string
1:
ldrb w2,[x0,x3]        // load byte of string
cmp x2,#'A'            // select alpha characters lower or upper
blt 5f
cmp x2,#'Z'
bgt 2f
sub x5,x2,#65          // convert ascii upper in index array (0-25)
b 3f
2:
cmp x2,#'z'
bgt 5f
cmp x2,#'a'
blt 5f
sub x5,x2,#97 - 26     // convert ascii lower in index array (26,52]
3:
str x7,[x4,x5,lsl #3]  // and store
5:
add x3,x3,#1           // increment text index
cmp x3,x1              // end ?
blt 1b                 // and loop

mov x2,65              // for upper ascci character
mov x3,#0
6:                         // result display
ldr x1,[x4,x3,lsl #3]  // load counter
cmp x1,#0              // if zero not display
beq 7f
cmp x3,#25             // upper ?
add x2,x3,65           // for upper ascci character
add x8,x3,#97 - 26     // lower
csel x6,x2,x8,le       // compute ascii character
strb w6,[x7,#9]        // store in message
mov x0,x1              // convert count in decimal
bl conversion10
bl affichageMess
bl affichageMess
bl affichageMess
7:
cmp x3,#52
blt 6b

100:
ldp x6,x7,[sp],16
ldp x4,x5,[sp],16
ldp x2,x3,[sp],16
ldp x1,lr,[sp],16                 // TODO: retaur à completer
ret
/***************************************************/
/*      ROUTINES INCLUDE                           */
/***************************************************/
/* for this file see task include a file in language AArch64 assembly*/
.include "../includeARM64.inc"```
Output:
```Program 64 bits start.
Result:  a = 16421
Result:  b = 4115
Result:  c = 8216
Result:  d = 5799
Result:  e = 20144
Result:  f = 2662
Result:  g = 4129
Result:  h = 5208
Result:  i = 13980
Result:  j = 430
Result:  k = 1925
Result:  l = 10061
Result:  m = 5828
Result:  n = 12097
Result:  o = 12738
Result:  p = 5516
Result:  q = 378
Result:  r = 13436
Result:  s = 10210
Result:  t = 12836
Result:  u = 6489
Result:  v = 1902
Result:  w = 1968
Result:  x = 617
Result:  y = 3633
Result:  z = 433
```

## ACL2

```(defun increment-alist (tbl key)
(cond ((endp tbl) (list (cons key 1)))
((eql (car (first tbl)) key)
(cons (cons key (1+ (cdr (first tbl))))
(rest tbl)))
(t (cons (first tbl)
(increment-alist (rest tbl) key)))))

(defun freq-table (xs)
(if (endp xs)
nil
(increment-alist (freq-table (rest xs))
(first xs))))

(defun letter-freq (str)
(freq-table (coerce str 'list)))
```

## Action!

```INCLUDE "D2:PRINTF.ACT" ;from the Action! Tool Kit

CARD ARRAY histogram(256)

PROC Clear()
INT i

FOR i=0 TO 255
DO histogram(i)=0 OD
RETURN

PROC ProcessLine(CHAR ARRAY line)
INT i

FOR i=1 TO line(0)
DO
histogram(line(i))==+1
OD
RETURN

PROC ProcessFile(CHAR ARRAY fname)
CHAR ARRAY line(255)
BYTE dev=

Close(dev)
Open(dev,fname,4)
WHILE Eof(dev)=0
DO
InputSD(dev,line)
ProcessLine(line)
OD
Close(dev)
RETURN

PROC PrintResult()
INT i
CHAR ARRAY s(10)

FOR i=0 TO 255
DO
IF histogram(i) THEN
StrC(histogram(i),s)
PrintF(" %C:%-5S",i,s)
FI
OD
RETURN

PROC Main()
CHAR ARRAY fname="H6:LETTE_KJ.ACT"
BYTE LMARGIN=\$52,old

old=LMARGIN
LMARGIN=0 ;remove left margin on the screen

Put(125) PutE() ;clear the screen
ProcessFile(fname)
PrintResult()

LMARGIN=old ;restore left margin on the screen
RETURN```
Output:
```Reading "H6:LETTE_KJ.ACT"...

:150   !:1     ":12    \$:1     %:5
(:27    ):27    +:1     ,:8     -:1
.:5     0:7     1:5     2:7     4:1
5:10    6:2     ::3     ;:4     =:13
A:25    B:2     C:19    D:12    E:16
F:10    G:4     H:8     I:13    J:1
K:2     L:9     M:5     N:15    O:20
P:16    R:44    S:4     T:20    U:6
W:1     Y:8     [:1     ]:1     _:1
a:16    c:9     d:10    e:49    f:9
g:8     h:9     i:36    l:20    m:14
n:29    o:23    p:2     r:25    s:24
t:24    u:5     v:7
```

```with Ada.Text_IO;

procedure Letter_Frequency is
Counters: array (Character) of Natural := (others => 0); -- initialize all Counters to 0
C:        Character;

begin
Counters(C) := Counters(C) + 1;
end loop;

for I in Counters'Range loop
if Counters(I) > 0 then
Ada.Text_IO.Put_Line("'" & I & "':" & Integer'Image(Counters(I)));
end if;
end loop;
end Letter_Frequency;
```
Output:
(counting the characters of its own source code)
```>./letter_frequency
' ': 122
'"': 6
'&': 3

... [a lot of lines omitted]

'x': 7
'y': 5
'z': 1```

## Aikido

```import ctype

var letters = new int 

var s = openin (args)
while (!s.eof()) {
var ch = s.getchar()
if (s.eof()) {
break
}
if (ctype.isalpha (ch)) {
var n = cast<int>(ctype.tolower(ch) - 'a')
++letters[n]
}
}

foreach i letters.size() {
println (cast<char>('a' + i) + " " + letters[i])
}```

## Aime

Letters proper:

```file f;
index x;
integer c;

f.affix("unixdict.txt");

while ((c = f.pick) ^ -1) {
x[c] += 1;
}

c = 'A';
while (c <= 'Z') {
o_form("%c: /w5/\n", c, x[c] += x[c + 'a' - 'A'] += 0);
c += 1;
}```

All chars:

```file f;
index x;
integer c, n;

f.affix("unixdict.txt");

while ((c = f.pick) ^ -1) {
x[c] += 1;
}

for (c, n in x) {
o_form("%c: /w5/\n", c, n);
}```

## ALGOL 68

```BEGIN
[0:max abs char]INT histogram;
FOR i FROM 0 TO max abs char DO histogram[i] := 0 OD;
FILE input file;
STRING input file name = "Letter_frequency.a68";
IF open (input file, input file name, stand in channel) /= 0 THEN
put (stand error, ("Cannot open ", input file name, newline));
stop
ELSE
on file end (input file, (REF FILE f) BOOL: (close (f); GOTO finished))
FI;
DO
STRING s;
get (input file, (s, newline));
FOR i TO UPB s DO
CHAR c = s[i];
IF "A" <= c AND c <= "Z" OR "a" <= c AND c <= "z" THEN
histogram[ABS c] PLUSAB 1
FI
OD
OD;
close (input file);
finished:
FOR i FROM ABS "A" TO ABS "Z" DO printf ((\$a3xg(0)l\$, REPR i, histogram[i])) OD;
FOR i FROM ABS "a" TO ABS "z" DO printf ((\$a3xg(0)l\$, REPR i, histogram[i])) OD
END```
Output:
Counting letters in its own source code
```A   11
B   9
C   2
D   13
E   11
F   14
G   4
H   3
I   10
J   0
[[ Omitted for K – Z and a – p ]]
q   1
r   15
s   19
t   24
u   10
v   0
w   3
x   4
y   1
z   2
```

## APL

```      freq←{(⍪∪⍵),+/(∪⍵)∘.⍷⍵}

freq 0 1 2 3 2 3 4 3 4 4 4
0 1
1 1
2 2
3 3
4 4

freq 'balloon'
b 1
a 1
l 2
o 2
n 1
```

The above solution doesn't do the "open a text file" part of the task. File I/O is implementation-dependent, but here's how to do it in Dyalog:

Works with: Dyalog APL
```      text ← ⊃⎕nget 'filename'
```

... after which the above freq function can be applied to text.

## AppleScript

### Procedural

This is probably best handled with vanilla AppleScript and ASObjC each each doing what it does best. The test text used here is the one specified for the Word frequency task.

```use AppleScript version "2.4" -- OS X 10.10 (Yosemite) or later
use framework "Foundation"

on letterFrequencyinFile(theFile)
-- Read the file as an NSString, letting the system guess the encoding.
set fileText to current application's class "NSString"'s stringWithContentsOfFile:(POSIX path of theFile) ¬
usedEncoding:(missing value) |error|:(missing value)
-- Get the NSString's non-letter delimited runs, lower-cased, as an AppleScript list of texts.
-- The switch to vanilla objects is for speed and the ability to extract 'characters'.
set nonLetterSet to current application's class "NSCharacterSet"'s letterCharacterSet()'s invertedSet()
script o
property letterRuns : (fileText's lowercaseString()'s componentsSeparatedByCharactersInSet:(nonLetterSet)) as list
end script

-- Extract the characters from the runs and add them to an NSCountedSet to have the occurrences of each value counted.
-- No more than 50,000 characters are extracted in one go to avoid slowing or freezing the script.
set countedSet to current application's class "NSCountedSet"'s new()
repeat with i from 1 to (count o's letterRuns)
set thisRun to item i of o's letterRuns
set runLength to (count thisRun)
repeat with i from 1 to runLength by 50000
set j to i + 49999
if (j > runLength) then set j to runLength
tell countedSet to addObjectsFromArray:(characters i thru j of thisRun)
end repeat
end repeat

-- Work through the counted set's contents and build a list of records showing how many of what it received.
set output to {}
repeat with thisLetter in countedSet's allObjects()
set thisCount to (countedSet's countForObject:(thisLetter))
set end of output to {letter:thisLetter, |count|:thisCount}
end repeat

-- Derive an array of dictionaries from the list and sort it on the letters.
set output to current application's class "NSMutableArray"'s arrayWithArray:(output)
set byLetter to current application's class "NSSortDescriptor"'s sortDescriptorWithKey:("letter") ¬
ascending:(true) selector:("localizedStandardCompare:")
tell output to sortUsingDescriptors:({byLetter})

-- Convert back to a list of records and return the result.
return output as list
end letterFrequencyinFile

-- Test with the text file for the "Word frequency" task.
set theFile to ((path to desktop as text) & "135-0.txt") as alias
return letterFrequencyinFile(theFile)
```
Output:
`{{letter:"a", |count|:207133}, {letter:"à", |count|:63}, {letter:"â", |count|:56}, {letter:"æ", |count|:116}, {letter:"b", |count|:37506}, {letter:"c", |count|:67354}, {letter:"ç", |count|:50}, {letter:"d", |count|:108747}, {letter:"e", |count|:330738}, {letter:"é", |count|:1474}, {letter:"è", |count|:299}, {letter:"ê", |count|:74}, {letter:"ë", |count|:5}, {letter:"f", |count|:56206}, {letter:"g", |count|:48598}, {letter:"h", |count|:176839}, {letter:"i", |count|:175288}, {letter:"î", |count|:39}, {letter:"ï", |count|:18}, {letter:"j", |count|:5840}, {letter:"k", |count|:14433}, {letter:"l", |count|:99543}, {letter:"m", |count|:62219}, {letter:"n", |count|:169954}, {letter:"ñ", |count|:2}, {letter:"o", |count|:184388}, {letter:"ô", |count|:34}, {letter:"œ", |count|:38}, {letter:"p", |count|:43387}, {letter:"q", |count|:2533}, {letter:"r", |count|:148671}, {letter:"s", |count|:162047}, {letter:"t", |count|:235526}, {letter:"u", |count|:68270}, {letter:"ù", |count|:18}, {letter:"û", |count|:9}, {letter:"ü", |count|:39}, {letter:"v", |count|:26268}, {letter:"w", |count|:56513}, {letter:"x", |count|:4027}, {letter:"y", |count|:39183}, {letter:"z", |count|:1906}}`

### Functional

#### Minimal new code

If we just want to get something up and running (and tabulating output) with a minimum of new code – enough to read the frequencies of shortish texts – we can quickly click together a composition of generic functions.

```use AppleScript version "2.4"
use framework "Foundation"

------------- CHARACTER COUNTS FROM FILE PATH -------------

-- charCounts :: FilePath -> Either String [(Char, Int)]
on charCounts(fp)
script go
on |λ|(s)
|Right|(sortBy(flip(comparing(my snd)), ¬
groupBy(my eq, sort(characters of s)))))
end |λ|
end script

end charCounts

-------------------------- TEST ---------------------------
on run
set intColumns to 4

either(identity, frequencyTabulation(intColumns), ¬

end run

------------------------- DISPLAY -------------------------

-- frequencyTabulation :: Int -> [(Char, Int)] -> String
on frequencyTabulation(intCols)
script
on |λ|(xs)
set w to length of (snd(item 1 of xs) as string)
script go
on |λ|(x)
justifyRight(5, " ", showChar(fst(x))) & ¬
" -> " & justifyRight(w, " ", snd(x) as string)
end |λ|
end script
showColumns(intCols, map(go, xs))
end |λ|
end script
end frequencyTabulation

-------------------- GENERIC FUNCTIONS --------------------

-- Left :: a -> Either a b
on |Left|(x)
{type:"Either", |Left|:x, |Right|:missing value}
end |Left|

-- Right :: b -> Either a b
on |Right|(x)
{type:"Either", |Left|:missing value, |Right|:x}
end |Right|

-- Tuple (,) :: a -> b -> (a, b)
on Tuple(a, b)
-- Constructor for a pair of values, possibly of two different types.
{type:"Tuple", |1|:a, |2|:b, length:2}
end Tuple

-- Absolute value.
-- abs :: Num -> Num
on abs(x)
if 0 > x then
-x
else
x
end if
end abs

-- bindLR (>>=) :: Either a -> (a -> Either b) -> Either b
on bindLR(m, mf)
if missing value is not |Left| of m then
m
else
mReturn(mf)'s |λ|(|Right| of m)
end if
end bindLR

-- chunksOf :: Int -> [a] -> [[a]]
on chunksOf(n, xs)
set lng to length of xs
script go
on |λ|(a, i)
set x to (i + n) - 1
if x ≥ lng then
a & {items i thru -1 of xs}
else
a & {items i thru x of xs}
end if
end |λ|
end script
foldl(go, {}, enumFromThenTo(1, 1 + n, lng))
end chunksOf

-- comparing :: (a -> b) -> (a -> a -> Ordering)
on comparing(f)
script
on |λ|(a, b)
tell mReturn(f)
set fa to |λ|(a)
set fb to |λ|(b)
if fa < fb then
-1
else if fa > fb then
1
else
0
end if
end tell
end |λ|
end script
end comparing

-- concatMap :: (a -> [b]) -> [a] -> [b]
on concatMap(f, xs)
set lng to length of xs
set acc to {}
tell mReturn(f)
repeat with i from 1 to lng
set acc to acc & (|λ|(item i of xs, i, xs))
end repeat
end tell
return acc
end concatMap

-- either :: (a -> c) -> (b -> c) -> Either a b -> c
on either(lf, rf, e)
if missing value is |Left| of e then
tell mReturn(rf) to |λ|(|Right| of e)
else
tell mReturn(lf) to |λ|(|Left| of e)
end if
end either

-- enumFromThenTo :: Int -> Int -> Int -> [Int]
on enumFromThenTo(x1, x2, y)
set xs to {}
set gap to x2 - x1
set d to max(1, abs(gap)) * (signum(gap))
repeat with i from x1 to y by d
set end of xs to i
end repeat
return xs
end enumFromThenTo

-- eq (==) :: Eq a => a -> a -> Bool
on eq(a, b)
a = b
end eq

-- Compose a function from a simple value to a tuple of
-- the separate outputs of two different functions
-- fanArrow (&&&) :: (a -> b) -> (a -> c) -> (a -> (b, c))
on fanArrow(f, g)
script
on |λ|(x)
Tuple(mReturn(f)'s |λ|(x), mReturn(g)'s |λ|(x))
end |λ|
end script
end fanArrow

-- flip :: (a -> b -> c) -> b -> a -> c
on flip(f)
script
property g : mReturn(f)
on |λ|(x, y)
g's |λ|(y, x)
end |λ|
end script
end flip

-- foldl :: (a -> b -> a) -> a -> [b] -> a
on foldl(f, startValue, xs)
tell mReturn(f)
set v to startValue
set lng to length of xs
repeat with i from 1 to lng
set v to |λ|(v, item i of xs, i, xs)
end repeat
return v
end tell
end foldl

-- fst :: (a, b) -> a
on fst(tpl)
if class of tpl is record then
|1| of tpl
else
item 1 of tpl
end if
end fst

-- Typical usage: groupBy(on(eq, f), xs)
-- groupBy :: (a -> a -> Bool) -> [a] -> [[a]]
on groupBy(f, xs)
set mf to mReturn(f)

script enGroup
on |λ|(a, x)
if length of (active of a) > 0 then
set h to item 1 of active of a
else
set h to missing value
end if

if h is not missing value and mf's |λ|(h, x) then
{active:(active of a) & {x}, sofar:sofar of a}
else
{active:{x}, sofar:(sofar of a) & {active of a}}
end if
end |λ|
end script

if length of xs > 0 then
set dct to foldl(enGroup, {active:{item 1 of xs}, sofar:{}}, rest of xs)
if length of (active of dct) > 0 then
sofar of dct & {active of dct}
else
sofar of dct
end if
else
{}
end if
end groupBy

-- head :: [a] -> a
if xs = {} then
missing value
else
item 1 of xs
end if

-- identity :: a -> a
on identity(x)
-- The argument unchanged.
x
end identity

-- justifyRight :: Int -> Char -> String -> String
on justifyRight(n, cFiller, strText)
if n > length of strText then
text -n thru -1 of ((replicate(n, cFiller) as text) & strText)
else
strText
end if
end justifyRight

-- length :: [a] -> Int
on |length|(xs)
set c to class of xs
if list is c or string is c then
length of xs
else
(2 ^ 29 - 1) -- (maxInt - simple proxy for non-finite)
end if
end |length|

-- map :: (a -> b) -> [a] -> [b]
on map(f, xs)
-- The list obtained by applying f
-- to each element of xs.
tell mReturn(f)
set lng to length of xs
set lst to {}
repeat with i from 1 to lng
set end of lst to |λ|(item i of xs, i, xs)
end repeat
return lst
end tell
end map

-- max :: Ord a => a -> a -> a
on max(x, y)
if x > y then
x
else
y
end if
end max

-- maximum :: Ord a => [a] -> a
on maximum(xs)
script
on |λ|(a, b)
if a is missing value or b > a then
b
else
a
end if
end |λ|
end script

foldl(result, missing value, xs)
end maximum

-- partition :: (a -> Bool) -> [a] -> ([a], [a])
on partition(f, xs)
tell mReturn(f)
set ys to {}
set zs to {}
repeat with x in xs
set v to contents of x
if |λ|(v) then
set end of ys to v
else
set end of zs to v
end if
end repeat
end tell
Tuple(ys, zs)
end partition

-- mReturn :: First-class m => (a -> b) -> m (a -> b)
on mReturn(f)
-- 2nd class handler function lifted into 1st class script wrapper.
if script is class of f then
f
else
script
property |λ| : f
end script
end if
end mReturn

-- readFileLR :: FilePath -> Either String IO String
set ca to current application
set e to reference
set {s, e} to (ca's NSString's ¬
stringWithContentsOfFile:((ca's NSString's ¬
stringWithString:strPath)'s ¬
stringByStandardizingPath) ¬
encoding:(ca's NSUTF8StringEncoding) |error|:(e))
if s is missing value then
|Left|((localizedDescription of e) as string)
else
|Right|(s as string)
end if

-- Egyptian multiplication - progressively doubling a list, appending
-- stages of doubling to an accumulator where needed for binary
-- assembly of a target length
-- replicate :: Int -> a -> [a]
on replicate(n, a)
set out to {}
if 1 > n then return out
set dbl to {a}

repeat while (1 < n)
if 0 < (n mod 2) then set out to out & dbl
set n to (n div 2)
set dbl to (dbl & dbl)
end repeat
return out & dbl
end replicate

-- showChar :: Char -> String
on showChar(c)
if space is c then
"SPACE"
else if tab is c then
"TAB"
else if linefeed is c then
"LF"
else
c
end if
end showChar

-- showColumns :: Int -> [String] -> String
on showColumns(n, xs)
set w to maximum(map(my |length|, xs))
set m to (length of xs) div n
unlines(map(my unwords, ¬
transpose(chunksOf(m, xs))))
end showColumns

-- signum :: Num -> Num
on signum(x)
if x < 0 then
-1
else if x = 0 then
0
else
1
end if
end signum

-- snd :: (a, b) -> b
on snd(tpl)
if class of tpl is record then
|2| of tpl
else
item 2 of tpl
end if
end snd

-- sort :: Ord a => [a] -> [a]
on sort(xs)
((current application's NSArray's arrayWithArray:xs)'s ¬
sortedArrayUsingSelector:"compare:") as list
end sort

-- Enough for small scale sorts.
-- Use instead sortOn (Ord b => (a -> b) -> [a] -> [a])
-- which is equivalent to the more flexible sortBy(comparing(f), xs)
-- and uses a much faster ObjC NSArray sort method
-- sortBy :: (a -> a -> Ordering) -> [a] -> [a]
on sortBy(f, xs)
if length of xs > 1 then
set h to item 1 of xs
set f to mReturn(f)
script
on |λ|(x)
f's |λ|(x, h) ≤ 0
end |λ|
end script
set lessMore to partition(result, rest of xs)
sortBy(f, |1| of lessMore) & {h} & ¬
sortBy(f, |2| of lessMore)
else
xs
end if
end sortBy

-- transpose :: [[String]] -> [[String]]
on transpose(rows)
script cols
on |λ|(_, iCol)
script cell
on |λ|(row)
if iCol > length of row then
""
else
item iCol of row
end if
end |λ|
end script
concatMap(cell, rows)
end |λ|
end script
map(cols, item 1 of rows)
end transpose

-- unlines :: [String] -> String
on unlines(xs)
-- A single string formed by the intercalation
-- of a list of strings with the newline character.
set {dlm, my text item delimiters} to ¬
{my text item delimiters, linefeed}
set str to xs as text
set my text item delimiters to dlm
str
end unlines

-- unwords :: [String] -> String
on unwords(xs)
set {dlm, my text item delimiters} to ¬
{my text item delimiters, space}
set s to xs as text
set my text item delimiters to dlm
return s
end unwords
```
Output:
```SPACE -> 1330     p ->  138     " ->   28     k ->    5
e ->  598     | ->  132     L ->   20     U ->    5
TAB ->  584     g ->  129     F ->   20     < ->    4
t ->  562     x ->  121     E ->   20     W ->    3
LF ->  509     > ->  107     I ->   18     G ->    3
n ->  462     : ->  102     O ->   17     / ->    3
s ->  423     , ->   98     B ->   17     V ->    2
- ->  384     y ->   70     A ->   17     H ->    2
i ->  372     b ->   70     & ->   17     D ->    2
o ->  365     R ->   42     ' ->   15     4 ->    2
r ->  316     λ ->   39     ¬ ->   13     + ->    2
a ->  311     w ->   39     N ->   13     ≥ ->    1
l ->  241     v ->   35     2 ->   13     ≤ ->    1
f ->  240     ] ->   35     = ->   12     ~ ->    1
d ->  198     [ ->   35     q ->   11     _ ->    1
) ->  181     C ->   35     0 ->   10     ^ ->    1
( ->  181     T ->   33     . ->    9     Y ->    1
m ->  154     S ->   32     P ->    8     9 ->    1
h ->  152     1 ->   31     M ->    8     8 ->    1
c ->  149     } ->   30     j ->    6     5 ->    1
u ->  141     { ->   30     z ->    5     * ->    1```

#### Minimal run-time

For longer texts, calculating only the frequencies of (case-insensitive and accent-insensitive) (a-z) alphabetics (and re-using here the Project Gutenburg Misérables text from the Word Frequency task), we can do something a little faster with a list of simple regular expressions, again composing a solution from existing generic functions.

```use AppleScript version "2.4"
use framework "Foundation"

------ CASE AND ACCENT-INSENSITIVE FREQUENCIES OF A-Z ----

-- romanLetterFrequencies :: FilePath -> Maybe [(Char, Int)]
on romanLetterFrequencies(fp)
if doesFileExist(fp) then
set patterns to enumFromToChar("a", "z")

set counts to ap(map(my matchCount, patterns), ¬
decomposedStringWithCanonicalMapping's ¬
lowercaseString})

sortBy(flip(comparing(my snd)))'s ¬
|λ|(zip(patterns, counts))
else
missing value
end if
end romanLetterFrequencies

--------------------------- TEST -------------------------
on run
set fpText to scriptFolder() & "miserables.txt"

set azFrequencies to romanLetterFrequencies(fpText)

if missing value is not azFrequencies then
script arrow
on |λ|(kv)
set {k, v} to kv
unwords({k, "->", v})
end |λ|
end script
unlines(map(arrow, azFrequencies))
else
display dialog "Text file not found in this script's folder:" & ¬
linefeed & tab & fpText
end if
end run

------------------------- GENERIC ------------------------

-- Tuple (,) :: a -> b -> (a, b)
on Tuple(a, b)
-- Constructor for a pair of values, possibly of two different types.
{a, b}
end Tuple

-- ap (<*>) :: [(a -> b)] -> [a] -> [b]
on ap(fs, xs)
-- e.g. [(*2),(/2), sqrt] <*> [1,2,3]
-- -->  ap([dbl, hlf, root], [1, 2, 3])
-- -->  [2,4,6,0.5,1,1.5,1,1.4142135623730951,1.7320508075688772]
-- Each member of a list of functions applied to
-- each of a list of arguments, deriving a list of new values
set lst to {}
repeat with f in fs
tell mReturn(contents of f)
repeat with x in xs
set end of lst to |λ|(contents of x)
end repeat
end tell
end repeat
return lst
end ap

-- comparing :: (a -> b) -> (a -> a -> Ordering)
on comparing(f)
script
on |λ|(a, b)
tell mReturn(f)
set fa to |λ|(a)
set fb to |λ|(b)
if fa < fb then
-1
else if fa > fb then
1
else
0
end if
end tell
end |λ|
end script
end comparing

-- doesFileExist :: FilePath -> IO Bool
on doesFileExist(strPath)
set ca to current application
set oPath to (ca's NSString's stringWithString:strPath)'s ¬
stringByStandardizingPath
set {bln, int} to (ca's NSFileManager's defaultManager's ¬
fileExistsAtPath:oPath isDirectory:(reference))
bln and (int ≠ 1)
end doesFileExist

-- enumFromToChar :: Char -> Char -> [Char]
on enumFromToChar(m, n)
set {intM, intN} to {id of m, id of n}
if intM ≤ intN then
set xs to {}
repeat with i from intM to intN
set end of xs to character id i
end repeat
return xs
else
{}
end if
end enumFromToChar

-- flip :: (a -> b -> c) -> b -> a -> c
on flip(f)
script
property g : mReturn(f)
on |λ|(x, y)
g's |λ|(y, x)
end |λ|
end script
end flip

-- map :: (a -> b) -> [a] -> [b]
on map(f, xs)
-- The list obtained by applying f
-- to each element of xs.
tell mReturn(f)
set lng to length of xs
set lst to {}
repeat with i from 1 to lng
set end of lst to |λ|(item i of xs, i, xs)
end repeat
return lst
end tell
end map

-- matchCount :: String -> NSString -> Int
on matchCount(regexString)
-- A count of the matches for a regular expression
-- in a given NSString
script
on |λ|(s)
set ca to current application
((ca's NSRegularExpression's ¬
regularExpressionWithPattern:regexString ¬
options:(ca's NSRegularExpressionAnchorsMatchLines) ¬
|error|:(missing value))'s ¬
numberOfMatchesInString:s ¬
options:0 ¬
range:{location:0, |length|:s's |length|()}) as integer
end |λ|
end script
end matchCount

-- min :: Ord a => a -> a -> a
on min(x, y)
if y < x then
y
else
x
end if
end min

-- mReturn :: First-class m => (a -> b) -> m (a -> b)
on mReturn(f)
-- 2nd class handler function lifted into 1st class script wrapper.
if script is class of f then
f
else
script
property |λ| : f
end script
end if
end mReturn

-- partition :: (a -> Bool) -> [a] -> ([a], [a])
on partition(f, xs)
tell mReturn(f)
set ys to {}
set zs to {}
repeat with x in xs
set v to contents of x
if |λ|(v) then
set end of ys to v
else
set end of zs to v
end if
end repeat
end tell
{ys, zs}
end partition

-- readFile :: FilePath -> IO NSString
set ca to current application
set e to reference
set {s, e} to (ca's NSString's ¬
stringWithContentsOfFile:((ca's NSString's ¬
stringWithString:strPath)'s ¬
stringByStandardizingPath) ¬
encoding:(ca's NSUTF8StringEncoding) |error|:(e))
if missing value is e then
s
else
(localizedDescription of e) as string
end if

-- scriptFolder :: () -> IO FilePath
on scriptFolder()
-- The path of the folder containing this script
tell application "Finder" to ¬
POSIX path of ((container of (path to me)) as alias)
end scriptFolder

-- snd :: (a, b) -> b
on snd(tpl)
item 2 of tpl
end snd

-- sortBy :: (a -> a -> Ordering) -> [a] -> [a]
on sortBy(f)
-- Enough for small scale sorts.
-- The NSArray sort method in the Foundation library
-- gives better permormance for longer lists.
script go
on |λ|(xs)
if length of xs > 1 then
set h to item 1 of xs
set f to mReturn(f)
script
on |λ|(x)
f's |λ|(x, h) ≤ 0
end |λ|
end script
set lessMore to partition(result, rest of xs)
|λ|(item 1 of lessMore) & {h} & ¬
|λ|(item 2 of lessMore)
else
xs
end if
end |λ|
end script
end sortBy

-- unlines :: [String] -> String
on unlines(xs)
-- A single string formed by the intercalation
-- of a list of strings with the newline character.
set {dlm, my text item delimiters} to ¬
{my text item delimiters, linefeed}
set s to xs as text
set my text item delimiters to dlm
s
end unlines

-- unwords :: [String] -> String
on unwords(xs)
set {dlm, my text item delimiters} to ¬
{my text item delimiters, space}
set s to xs as text
set my text item delimiters to dlm
return s
end unwords

-- zip :: [a] -> [b] -> [(a, b)]
on zip(xs, ys)
zipWith(Tuple, xs, ys)
end zip

-- zipWith :: (a -> b -> c) -> [a] -> [b] -> [c]
on zipWith(f, xs, ys)
set lng to min(length of xs, length of ys)
set lst to {}
if 1 > lng then
return {}
else
tell mReturn(f)
repeat with i from 1 to lng
set end of lst to |λ|(item i of xs, item i of ys)
end repeat
return lst
end tell
end if
end zipWith
```
Output:
```e -> 332590
t -> 235526
a -> 207252
o -> 184422
h -> 176839
i -> 175345
n -> 169956
s -> 162047
r -> 148671
d -> 108747
l -> 99543
u -> 68336
c -> 67404
m -> 62219
w -> 56513
f -> 56206
g -> 48598
p -> 43387
y -> 39183
b -> 37506
v -> 26268
k -> 14433
j -> 5840
x -> 4027
q -> 2533
z -> 1906```

## Applesoft BASIC

``` 100  LET F\$ = "TEXT FILE"
110  LET D\$ =  CHR\$ (4)
120  DIM C(255)
130  PRINT D\$"OPEN "F\$
140  FOR Q = 0 TO 1 STEP 0
160      ONERR  GOTO 240
170      GET C\$
180      POKE 216,0
190      LET C =  ASC (C\$)
200      LET C(C) = C(C) + 1
210      PRINT
220  NEXT
230  STOP
240  POKE 216,0
250  LET E =  PEEK (222)
260  PRINT D\$"CLOSE "F\$
270  IF E <  > 5 THEN  RESUME
280  FOR I = 0 TO 255
290      IF C(I) THEN  GOSUB 320
300  NEXT I
310  END
320  IF I < 32 THEN  PRINT "^" CHR\$ (64 + I);
330  IF I >  = 32 AND I < 128 THEN  PRINT  CHR\$ (I);
340  IF I > 127 THEN  PRINT "CHR\$("I")";
350  PRINT "="C(I)"  ";
360  RETURN```

## ARM Assembly

Works with: as version Raspberry Pi
or android 32 bits with application Termux
```/* ARM assembly Raspberry PI  */
/*  program cptletters.s   */

/************************************/
/* Constantes                       */
/************************************/
/* for this file see task include a file in language ARM assembly*/
.include "../constantes.inc"
.equ WRITE,  4
.equ OPEN,   5
.equ CLOSE,  6
.equ O_RDWR,  0x0002         @ open for reading and writing
.equ BUFFERSIZE, 300000
/************************************/
/* Initialized data                 */
/************************************/
.data
szMessOpen:           .asciz "File open error.\n"
szMessStat:           .asciz "File information error.\n"
szMessClose:          .asciz "File close error.\n"
szMessDecryptText:    .asciz "Decrypted text :\n"
szMessCryptText:      .asciz "Encrypted text :\n"
szMessErrorChar:      .asciz "Character text not Ok!\n"
szFileName:           .asciz "unixdict.txt"
//szFileName:           .asciz "test1.txt"
szMessResult:         .asciz "Result:    = "
szCarriageReturn:     .asciz "\n"
szMessStart:          .asciz "Program 32 bits start.\n"
/************************************/
/* UnInitialized data               */
/************************************/
.bss
sZoneConv:            .skip 24
tabCptLetters:        .skip 4 * 52         @ (A-Z a-z) counter array
sBuffer:              .skip BUFFERSIZE     @ file buffer
/************************************/
/*  code section                    */
/************************************/
.text
.global main
main:                        @ entry of program
bl affichageMess
mov r1,#O_RDWR           @ flags
mov r2,#0                @ mode
mov r7,#OPEN             @ file open
svc 0
cmp r0,#0                @ error ?
ble 99f
mov r8,r0                @ FD save

mov r0,r8
ldr r2,#iBufferSize
svc 0
cmp r0,#0                @ error read ?
blt 97f
mov r6,r0                @ file size
mov r0,r8
mov r7,#CLOSE            @ call system close file
svc 0
cmp r0,#0                @ error close ?
blt 96f
mov r1,r6
bl cptLetters

b 100f
96:
bl affichageMess
mov r0,#-1               @ error
b 100f
97:
bl affichageMess
mov r0,#-1               @ error
b 100f
99:
bl  affichageMess
mov r0,#-1               @ error

100:                         @ standard end of the program
mov r0, #0               @ return code
mov r7, #EXIT            @ request to exit program
svc 0                    @ perform the system call

iBufferSize:              .int BUFFERSIZE
/***************************************************/
/*   letters frequency                   */
/***************************************************/
/* r0 contains a file buffer */
/* r1 contains string length */
cptLetters:
push {r1-r7,lr}        @ save registers
mov r3,#0              @ index string
1:
ldrb r2,[r0,r3]        @ load byte of string
cmp r2,#'A'            @ select alpha characters lower or upper
blt 5f
cmp r2,#'Z'
bgt 2f
sub r5,r2,#65          @ convert ascii upper in index array (0-25)
b 3f
2:
cmp r2,#'z'
bgt 5f
cmp r2,#'a'
blt 5f
sub r5,r2,#97 - 26     @ convert ascii lower in index array (26,52]
3:
str r7,[r4,r5,lsl #2]  @ and store
5:
add r3,r3,#1           @ increment text index
cmp r3,r1              @ end ?
blt 1b                 @ and loop

mov r3,#0
6:                         @ result display
ldr r1,[r4,r3,lsl #2]  @ load counter
cmp r1,#0              @ if zero not display
beq 7f
cmp r3,#25             @ upper ?
addle r6,r3,#65        @ yes compute ascci character
addgt r6,r3,#97 - 26   @ lower
strb r6,[r7,#9]        @ store in message
mov r0,r1              @ convert count in decimal
bl conversion10
bl affichageMess
bl affichageMess
bl affichageMess
7:
cmp r3,#52
blt 6b

100:
pop {r1-r7,pc}
/***************************************************/
/*      ROUTINES INCLUDE                           */
/***************************************************/
/* for this file see task include a file in language ARM assembly*/
.include "../affichage.inc"```
Output:

with the file unixdict.txt

```Program 32 bits start.
Result:  a = 16421
Result:  b = 4115
Result:  c = 8216
Result:  d = 5799
Result:  e = 20144
Result:  f = 2662
Result:  g = 4129
Result:  h = 5208
Result:  i = 13980
Result:  j = 430
Result:  k = 1925
Result:  l = 10061
Result:  m = 5828
Result:  n = 12097
Result:  o = 12738
Result:  p = 5516
Result:  q = 378
Result:  r = 13436
Result:  s = 10210
Result:  t = 12836
Result:  u = 6489
Result:  v = 1902
Result:  w = 1968
Result:  x = 617
Result:  y = 3633
Result:  z = 433
```

## Arturo

```source: {
The Red Death had long devastated the country.
No pestilence had ever been so fatal, or so hideous.
Blood was its Avator and its seal—the redness and the horror of blood.
There were sharp pains, and sudden dizziness,
and then profuse bleeding at the pores, with dissolution.
The scarlet stains upon the body and especially upon the face of the victim,
were the pest ban which shut him out from the aid and from the sympathy of his fellow-men.
And the whole seizure, progress and termination of the disease,
were the incidents of half an hour.
}

valid: split "abcdefghijklmnopqrstuvwxyz"
frequencies: #[]

loop split lower source 'ch [
if in? ch valid [
if not? key? frequencies ch ->
set frequencies ch 0

set frequencies ch (get frequencies ch)+1
]
]

inspect.muted frequencies
```
Output:
```[ :dictionary
t  :	39 :integer
h  :	33 :integer
e  :	60 :integer
r  :	24 :integer
d  :	27 :integer
a  :	33 :integer
l  :	15 :integer
o  :	34 :integer
n  :	30 :integer
g  :	3 :integer
v  :	4 :integer
s  :	34 :integer
c  :	8 :integer
u  :	11 :integer
y  :	5 :integer
p  :	11 :integer
i  :	25 :integer
b  :	6 :integer
f  :	12 :integer
w  :	8 :integer
z  :	3 :integer
m  :	7 :integer
]```

## AutoHotkey

This is the past version of this edit but made into a function, and now it only shows the letters that are in it, but not the ones with 0 letters

```LetterFreq(Var) {
Loop, 26
{
StrReplace(Var, Chr(96+A_Index), , Count)
if Count
out .= Chr(96+A_Index) ": " Count "`n"
}
return out
}

var := "The dog jumped over the lazy fox"
var2 := "foo bar"
Msgbox, % LetterFreq(var)
Msgbox, % LetterFreq(var2)
```
Output:
```a: 1
d: 2
e: 4
f: 1
g: 1
h: 2
j: 1
l: 1
m: 1
o: 3
p: 1
r: 1
t: 2
u: 1
v: 1
x: 1
y: 1
z: 1
---------------------------
---------------------------
a: 1
b: 1
f: 1
o: 2
r: 1```

## AutoIt

This function prints the Letter frequency of a given textfile. You can choose to use case sensitive search and if special chars should be searched too.

```Func _Letter_frequency(\$Path, \$fcase = True, \$fspecial_chars = True)
Local \$hFile, \$sRead, \$iupto, \$iStart, \$iCount
If Not \$fcase Then \$fcase = False
If Not \$fspecial_chars Then
\$iStart = 64
If Not \$fcase Then
\$iupto = 26
Else
\$iupto = 58
EndIf
Else
\$iStart = 31
\$iupto = 224
EndIf
\$hFile = FileOpen(\$Path, 0)
FileClose(\$hFile)
For \$i = 1 To \$iupto
If Not \$fspecial_chars Then
If \$iStart + \$i > 90 And \$iStart + \$i < 97 Then ContinueLoop
EndIf
\$iCount = @extended
If \$iCount > 0 Then ConsoleWrite(Chr(\$iStart + \$i) & " : " & \$iCount & @CRLF)
Next
EndFunc   ;==>_Letter_frequency
```
Output:
```A : 32
B : 2
C : 15
E : 31
F : 10
[several lines omitted]
u : 14
v : 1
w : 1
x : 14```

## AWK

```# usage: awk -f letters.awk HolyBible.txt

BEGIN { FS="" }
{ for(i=1;i<=NF;i++) m[\$i]++}
END   { for(i in m) printf("%9d %-14s\n", m[i],i) }
```

## BaCon

```txt\$ = LOAD\$("bible.txt")

FOR x = 97 TO 122
PRINT CHR\$(x-32), " ", CHR\$(x), " : ", COUNT(txt\$, x-32), " - ", COUNT(txt\$, x)
NEXT```
Output:
```A a : 17915 - 257815
B b : 4714 - 44161
C c : 1698 - 53373
D d : 8782 - 149313
E e : 2710 - 409525
F f : 2386 - 81157
G g : 6206 - 49096
H h : 3208 - 279471
I i : 13302 - 180660
J j : 6374 - 2515
K k : 547 - 21745
L l : 9222 - 120716
M m : 3056 - 76884
N n : 1891 - 223166
O o : 8896 - 234290
P p : 1877 - 41377
Q q : 6 - 958
R r : 7568 - 162761
S s : 4906 - 185124
T t : 7763 - 309983
U u : 333 - 83140
V v : 107 - 30258
W w : 2408 - 63079
X x : 2 - 1476
Y y : 569 - 58007
Z z : 904 - 2068
```

## BBC BASIC

```      DIM cnt%(255)

file% = OPENIN("C:\unixdict.txt")
IF file%=0 ERROR 100, "Could not open file"

REPEAT
A\$ = GET\$#file%
L% = LEN(A\$)
IF L% THEN
FOR I% = 1 TO L%
cnt%(ASCMID\$(A\$,I%)) += 1
NEXT
ENDIF
UNTIL EOF#file%
CLOSE #file%

FOR c% = &41 TO &5A
PRINT CHR\$(c%)CHR\$(c%+32) ": " cnt%(c%)+cnt%(c%+32)
NEXT
```
Output:
```Aa:      16421
Bb:       4115
Cc:       8216
Dd:       5799
Ee:      20144
Ff:       2662
Gg:       4129
Hh:       5208
Ii:      13980
Jj:        430
Kk:       1925
Ll:      10061
Mm:       5828
Nn:      12097
Oo:      12738
Pp:       5516
Qq:        378
Rr:      13436
Ss:      10210
Tt:      12836
Uu:       6489
Vv:       1902
Ww:       1968
Xx:        617
Yy:       3633
Zz:        433
```

## BCPL

```get "libhdr"

let start() be
\$(  let count = vec 255
let file = findinput("unixdict.txt")

for i = 0 to 255 do i!count := 0

selectinput(file)
\$(  let ch = rdch()
if ch = endstreamch then break
ch!count := ch!count + 1
\$) repeat

for i = 'A' to 'Z' do
\$(  let n = i!count + (i|32)!count
unless n = 0 do
writef("%C%C: %I5*N", i, i|32, n)
\$)

\$)```
Output:
```Aa: 16421
Bb:  4115
Cc:  8216
Dd:  5799
Ee: 20144
Ff:  2662
Gg:  4129
Hh:  5208
Ii: 13980
Jj:   430
Kk:  1925
Ll: 10061
Mm:  5828
Nn: 12097
Oo: 12738
Pp:  5516
Qq:   378
Rr: 13436
Ss: 10210
Tt: 12836
Uu:  6489
Vv:  1902
Ww:  1968
Xx:   617
Yy:  3633
Zz:   433```

## BQN

`"sample.txt"` can be substituted with any filename.

```Freq←⍷≍/⁼∘⊐

Freq "balloon"
# For a file:
Freq •FLines "sample.txt"
```
```┌─
╵ 'b' 'a' 'l' 'o' 'n'
1   1   2   2   1
┘
```

## Bracmat

```(lc=
counts c
.     fil\$(!arg,r)                        {open file for reading}
& 0:?counts
&   whl
' ( fil\$:?c                         {read a byte}
&     ( !c:(~<A:~>Z|~<a:~>z)
| 0
)
+ !counts
: ?counts                       {simply add any found letter to the sum}
)
& fil\$(,SET,-1)                       {close the file by seeking to impossible file position.}
| !counts                               {return the sum}
);

lc\$"valid.bra"                            {example: count letters in Bracmat's validation suite.}```
```107*A
+ 33*B
+ 37*C
+ 39*D
+ 74*E
+ 50*F
+ 27*G
+ 28*H
+ 20*I
+ 55*J
+ 32*K
+ 112*L
+ 36*M
+ 32*N
+ 621*O
+ 43*P
+ 25*R
+ 67*S
+ 62*T
+ 64*U
+ 5*V
+ 26*W
+ 353*X
+ 248*Y
+ 70*Z
+ 2173*a
+ 840*b
+ 738*c
+ 639*d
+ 1345*e
+ 472*f
+ 372*g
+ 568*h
+ 91*j
+ 142*k
+ 529*l
+ 409*m
+ 941*n
+ 840*o
+ 336*p
+ 65*q
+ 993*r
+ 1018*s
+ 2097*t
+ 978*u
+ 122*v
+ 156*w
+ 909*x
+ 685*y
+ 211*z
+ 1035*i```

## C

```/* declare array */
int frequency;
int ch;
FILE* txt_file = fopen ("a_text_file.txt", "rt");

/* init the freq table: */
for (ch = 0; ch < 26; ch++)
frequency[ch] = 0;

while (1) {
ch = fgetc(txt_file);
if (ch == EOF) break; /* end of file or read error.  EOF is typically -1 */

/* assuming ASCII; "letters" means "a to z" */
if ('a' <= ch && ch <= 'z')      /* lower case */
frequency[ch-'a']++;
else if ('A' <= ch && ch <= 'Z') /* upper case */
frequency[ch-'A']++;
}
```

## C#

```using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

class Program
{
static SortedDictionary<TItem, int> GetFrequencies<TItem>(IEnumerable<TItem> items)
{
var dictionary = new SortedDictionary<TItem, int>();
foreach (var item in items)
{
if (dictionary.ContainsKey(item))
{
dictionary[item]++;
}
else
{
dictionary[item] = 1;
}
}
return dictionary;
}

static void Main(string[] arguments)
{
var file = arguments.FirstOrDefault();
if (File.Exists(file))
{
foreach (var entry in GetFrequencies(text))
{
Console.WriteLine("{0}: {1}", entry.Key, entry.Value);
}
}
}
}
```
Output:
``` : 1
!: 1
,: 1
H: 1
d: 1
e: 1
l: 3
o: 2
r: 1
w: 1```

Declarative approach:

```var freq =  from c in str
where char.IsLetter(c)
orderby c
group c by c into g
select g.Key + ":" + g.Count();

foreach(var g in freq)
Console.WriteLine(g);
```
```C:2
I:1
K:1
L:2
W:1
a:4
...
y:2
```

## C++

```#include <fstream>
#include <iostream>

int main()
{
std::ifstream input("filename.txt", std::ios_base::binary);
if (!input)
{
std::cerr << "error: can't open file\n";
return -1;
}

size_t count;
std::fill_n(count, 256, 0);

for (char c; input.get(c); ++count[uint8_t(c)]) // process input file
; // empty loop body

for (size_t i = 0; i < 256; ++i)
{
if (count[i] && isgraph(i)) // non-zero counts of printable characters
{
std::cout << char(i) << " = " << count[i] << '\n';
}
}
}
```
Output:
when file contains "Hello, world!" (without quotes)
```! = 1
, = 1
H = 1
d = 1
e = 1
l = 3
o = 2
r = 1
w = 1
```

## Clojure

```(println (sort-by second >
(frequencies (map #(java.lang.Character/toUpperCase %)
(filter #(java.lang.Character/isLetter %) (slurp "text.txt"))))))
```

## Common Lisp

```(defun letter-freq (file)
(with-open-file (stream file)
(let ((str (make-string (file-length stream)))
(arr (make-array 256 :element-type 'integer :initial-element 0)))
(loop for c across str do (incf (aref arr (char-code c))))
(loop for c from 32 to 126 for i from 1 do
(format t "~c: ~d~a"
(code-char c) (aref arr c)
(if (zerop (rem i 8)) #\newline #\tab))))))

(letter-freq "test.lisp")
```

## COBOL

```       IDENTIFICATION DIVISION.
PROGRAM-ID. Letter-Frequency.
AUTHOR.  Bill Gunshannon.
INSTALLATION.  Home.
DATE-WRITTEN.  12 December 2021.
************************************************************
** Program Abstract:
**   A rather simplistic program to do the kind of thing
**   that COBOL does really well.
************************************************************

ENVIRONMENT DIVISION.

INPUT-OUTPUT SECTION.
FILE-CONTROL.
SELECT Text-File ASSIGN TO "File.txt"
ORGANIZATION IS LINE SEQUENTIAL.

DATA DIVISION.

FILE SECTION.

FD  Text-File
DATA RECORD IS Record-Name.
01  Record-Name           PIC X(80).

WORKING-STORAGE SECTION.

01 Eof                   PIC X     VALUE 'F'.

01  Letter-cnt.
05  A-cnt            PIC 9(5)    VALUE 0.
05  B-cnt            PIC 9(5)    VALUE 0.
05  C-cnt            PIC 9(5)    VALUE 0.
05  D-cnt            PIC 9(5)    VALUE 0.
05  E-cnt            PIC 9(5)    VALUE 0.
05  F-cnt            PIC 9(5)    VALUE 0.
05  G-cnt            PIC 9(5)    VALUE 0.
05  H-cnt            PIC 9(5)    VALUE 0.
05  I-cnt            PIC 9(5)    VALUE 0.
05  J-cnt            PIC 9(5)    VALUE 0.
05  K-cnt            PIC 9(5)    VALUE 0.
05  L-cnt            PIC 9(5)    VALUE 0.
05  M-cnt            PIC 9(5)    VALUE 0.
05  N-cnt            PIC 9(5)    VALUE 0.
05  O-cnt            PIC 9(5)    VALUE 0.
05  P-cnt            PIC 9(5)    VALUE 0.
05  Q-cnt            PIC 9(5)    VALUE 0.
05  R-cnt            PIC 9(5)    VALUE 0.
05  S-cnt            PIC 9(5)    VALUE 0.
05  T-cnt            PIC 9(5)    VALUE 0.
05  U-cnt            PIC 9(5)    VALUE 0.
05  V-cnt            PIC 9(5)    VALUE 0.
05  W-cnt            PIC 9(5)    VALUE 0.
05  X-cnt            PIC 9(5)    VALUE 0.
05  Y-cnt            PIC 9(5)    VALUE 0.
05  Z-cnt            PIC 9(5)    VALUE 0.

01  Letter-disp.
05  A-cnt            PIC ZZZZ9.
05  B-cnt            PIC ZZZZ9.
05  C-cnt            PIC ZZZZ9.
05  D-cnt            PIC ZZZZ9.
05  E-cnt            PIC ZZZZ9.
05  F-cnt            PIC ZZZZ9.
05  G-cnt            PIC ZZZZ9.
05  H-cnt            PIC ZZZZ9.
05  I-cnt            PIC ZZZZ9.
05  J-cnt            PIC ZZZZ9.
05  K-cnt            PIC ZZZZ9.
05  L-cnt            PIC ZZZZ9.
05  M-cnt            PIC ZZZZ9.
05  N-cnt            PIC ZZZZ9.
05  O-cnt            PIC ZZZZ9.
05  P-cnt            PIC ZZZZ9.
05  Q-cnt            PIC ZZZZ9.
05  R-cnt            PIC ZZZZ9.
05  S-cnt            PIC ZZZZ9.
05  T-cnt            PIC ZZZZ9.
05  U-cnt            PIC ZZZZ9.
05  V-cnt            PIC ZZZZ9.
05  W-cnt            PIC ZZZZ9.
05  X-cnt            PIC ZZZZ9.
05  Y-cnt            PIC ZZZZ9.
05  Z-cnt            PIC ZZZZ9.

PROCEDURE DIVISION.

Main-Program.
OPEN INPUT  Text-File
PERFORM UNTIL Eof = 'T'
AT END MOVE 'T' to Eof
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING A-cnt OF Letter-cnt  FOR ALL 'A'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING B-cnt OF Letter-cnt  FOR ALL 'B'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING C-cnt OF Letter-cnt  FOR ALL 'C'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING D-cnt OF Letter-cnt  FOR ALL 'D'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING E-cnt OF Letter-cnt  FOR ALL 'E'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING F-cnt OF Letter-cnt  FOR ALL 'F'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING G-cnt OF Letter-cnt  FOR ALL 'G'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING H-cnt OF Letter-cnt  FOR ALL 'H'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING I-cnt OF Letter-cnt  FOR ALL 'I'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING J-cnt OF Letter-cnt  FOR ALL 'J'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING K-cnt OF Letter-cnt  FOR ALL 'K'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING L-cnt OF Letter-cnt  FOR ALL 'L'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING M-cnt OF Letter-cnt  FOR ALL 'M'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING N-cnt OF Letter-cnt  FOR ALL 'N'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING O-cnt OF Letter-cnt  FOR ALL 'O'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING P-cnt OF Letter-cnt  FOR ALL 'P'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING Q-cnt OF Letter-cnt  FOR ALL 'Q'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING R-cnt OF Letter-cnt  FOR ALL 'R'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING S-cnt OF Letter-cnt  FOR ALL 'S'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING T-cnt OF Letter-cnt  FOR ALL 'T'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING U-cnt OF Letter-cnt  FOR ALL 'U'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING V-cnt OF Letter-cnt  FOR ALL 'V'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING W-cnt OF Letter-cnt  FOR ALL 'W'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING X-cnt OF Letter-cnt  FOR ALL 'X'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING Y-cnt OF Letter-cnt  FOR ALL 'Y'
INSPECT FUNCTION UPPER-CASE(Record-Name)
TALLYING Z-cnt OF Letter-cnt  FOR ALL 'Z'
END-PERFORM.
CLOSE Text-File.
MOVE CORRESPONDING Letter-cnt To Letter-disp.
DISPLAY 'Letter Frequency Distribution'.
DISPLAY '-----------------------------'.
DISPLAY 'A : ' A-cnt OF Letter-disp '          '
'N : ' N-cnt OF Letter-disp.
DISPLAY 'B : ' B-cnt OF Letter-disp '          '
'O : ' O-cnt OF Letter-disp.
DISPLAY 'C : ' C-cnt OF Letter-disp '          '
'P : ' P-cnt OF Letter-disp.
DISPLAY 'D : ' D-cnt OF Letter-disp '          '
'Q : ' Q-cnt OF Letter-disp.
DISPLAY 'E : ' E-cnt OF Letter-disp '          '
'R : ' R-cnt OF Letter-disp.
DISPLAY 'F : ' F-cnt OF Letter-disp '          '
'S : ' S-cnt OF Letter-disp.
DISPLAY 'G : ' G-cnt OF Letter-disp '          '
'T : ' T-cnt OF Letter-disp.
DISPLAY 'H : ' H-cnt OF Letter-disp '          '
'U : ' U-cnt OF Letter-disp.
DISPLAY 'I : ' I-cnt OF Letter-disp '          '
'V : ' V-cnt OF Letter-disp.
DISPLAY 'J : ' J-cnt OF Letter-disp '          '
'W : ' W-cnt OF Letter-disp.
DISPLAY 'K : ' K-cnt OF Letter-disp '          '
'X : ' X-cnt OF Letter-disp.
DISPLAY 'L : ' L-cnt OF Letter-disp '          '
'Y : ' Y-cnt OF Letter-disp.
DISPLAY 'M : ' M-cnt OF Letter-disp '          '
'Z : ' Z-cnt OF Letter-disp.
STOP RUN.

END-PROGRAM.
```
Output:
```Letter Frequency Distribution
-----------------------------
A :   416          N :   434
B :   120          O :   545
C :   316          P :   215
D :   267          Q :    12
E :   679          R :   436
F :   122          S :   432
G :   171          T :   493
H :   131          U :   180
I :   429          V :    57
J :    12          W :    97
K :    17          X :    35
L :   303          Y :    50
M :   162          Z :    60
```

## Component Pascal

BlackBox Component Builder

```MODULE LetterFrecuency;
IMPORT Files,StdLog,Strings;

PROCEDURE Do*;
VAR
loc: Files.Locator;
fd: Files.File;
x: BYTE;
frecuency: ARRAY 26 OF LONGINT;
c: CHAR;
i: INTEGER;
BEGIN
loc := Files.dir.This("BBTest/Mod");
fd := Files.dir.Old(loc,"LetterFrecuency.odc",FALSE);

(* init the frecuency array *)
FOR i := 0 TO LEN(frecuency) - 1 DO frecuency[i] := 0 END;

(* collect frecuencies *)
WHILE ~rd.eof DO
(* convert vowels with diacritics *)
CASE ORD(c) OF
193: c := 'A';
|201: c := 'E';
|205: c := 'I';
|211: c := 'O';
|218: c := 'U';
ELSE
END;
IF (c >= 'A') & (c <= 'Z') THEN
INC(frecuency[ORD(c) - ORD('A')]);
END
END;

(* show data *)
FOR i := 0 TO LEN(frecuency) - 1 DO
StdLog.Char(CHR(i + ORD('A')));StdLog.String(":> ");StdLog.Int(frecuency[i]);
StdLog.Ln
END
END Do;
END LetterFrecuency.```

Execute: ^Q LetterFrecuency.Do

Output:
```A:>  28
B:>  7
C:>  100
D:>  94
E:>  168
F:>  30
G:>  10
H:>  11
I:>  49
J:>  0
K:>  1
L:>  67
M:>  25
N:>  57
O:>  81
P:>  3
Q:>  0
R:>  91
S:>  90
T:>  94
U:>  32
V:>  14
W:>  15
X:>  15
Y:>  17
Z:>  3
```

## Cowgol

```include "cowgol.coh";
include "argv.coh";
include "file.coh";

# Get filename from command line
ArgvInit();
var file := ArgvNext();
if file == (0 as [uint8]) then
print("error: no file name\n");
ExitWithError();
end if;

# Open the file
var fcb: FCB;
if FCBOpenIn(&fcb, file) != 0 then
print("error: cannot open file\n");
ExitWithError();
end if;

# Counters for each letter
var letterCount: uint32;
MemZero(&letterCount as [uint8], @bytesof letterCount);

# Count every letter
var len := FCBExt(&fcb);
while len != 0 loop
len := len - 1;
var ch := (FCBGetChar(&fcb) | 32) - 'a';
if ch >= @sizeof letterCount then
continue;
end if;
letterCount[ch] := letterCount[ch] + 1;
end loop;

# Close the file
var foo := FCBClose(&fcb);

# Print value for each letter
ch := 0;
while ch < @sizeof letterCount loop
print_char(ch + 'A');
print(": ");
print_i32(letterCount[ch]);
print_nl();
ch := ch + 1;
end loop;```
Output:

The result of running the program on its own source file:

```A: 22
B: 11
C: 46
D: 9
E: 80
F: 32
G: 6
H: 26
I: 42
J: 0
K: 0
L: 39
M: 7
N: 53
O: 45
P: 14
Q: 0
R: 47
S: 8
T: 59
U: 18
V: 11
W: 5
X: 4
Y: 2
Z: 3```

## D

```void main() {
import std.stdio, std.ascii, std.algorithm, std.range;

uint frequency;

foreach (const buffer; "unixdict.txt".File.byChunk(2 ^^ 15))
foreach (immutable c; buffer.filter!isAlpha)
frequency[c.toLower - 'a']++;

writefln("%(%(%s, %),\n%)", frequency[].chunks(10));
}
```
Output:
```16421, 4115, 8216, 5799, 20144, 2662, 4129, 5208, 13980, 430,
1925, 10061, 5828, 12097, 12738, 5516, 378, 13436, 10210, 12836,
6489, 1902, 1968, 617, 3633, 433```

See Pascal.

## Draco

```proc nonrec main() void:
file() infile;
 char linebuf;
 word count;
*char line;
char c;
byte i;
word n;
channel input text filech;
channel input text linech;

for i from 0 upto 255 do count[i] := 0 od;
line := &linebuf;

open(filech, infile, "unixdict.txt");
open(linech, line);
i := pretend(c, byte);
count[i] := count[i] + 1
od;
close(linech)
od;
close(filech);

for c from 'A' upto 'Z' do
i := pretend(c, byte);
n := count[i] + count[i | 32];
writeln(c, pretend(i | 32, char), ": ", n:5)
od
corp```
Output:
```Aa: 16421
Bb:  4115
Cc:  8216
Dd:  5799
Ee: 20144
Ff:  2662
Gg:  4129
Hh:  5208
Ii: 13980
Jj:   430
Kk:  1925
Ll: 10061
Mm:  5828
Nn: 12097
Oo: 12738
Pp:  5516
Qq:   378
Rr: 13436
Ss: 10210
Tt: 12836
Uu:  6489
Vv:  1902
Ww:  1968
Xx:   617
Yy:  3633
Zz:   433```

## EasyLang

```len d[] 26
repeat
s\$ = input
until s\$ = ""
for c\$ in strchars s\$
c = strcode c\$
if c >= 97 and c <= 122
c -= 32
.
if c >= 65 and c <= 91
d[c - 64] += 1
.
.
.
for i to 26
write strchar (96 + i) & ": "
print d[i]
.
input_data
Open a text file and count the occurrences of each letter.
Some of these programs count all characters (including
punctuation), but some only count letters A to Z.
Other tasks related to string operations:```

## EchoLisp

We use a property list - plist for short - which is a hash table, to store the pairs ( letter . count) .

```;; bump count when letter added
(define (hash-counter hash key )
;; (set! key (string-downcase key)) - if ignore case wanted
(putprop hash (1+ (or (getprop hash key) 0 )) key))

;;  apply to exploded string
;;  and sort result
(define (hash-compare a b) ( < (first a) (first b)))
(define (count-letters hash string)
(map (curry hash-counter hash) (string->list string))
(list-sort hash-compare (symbol-plist hash)))
```
Output:
```(define (file-stats file string)
(set-plist! 'file-stats null) ; reset counters
(writeln (count-letters 'file-stats string))
(writeln "Total letters:" (string-length string))
(writeln "Total lines:" (getprop 'file-stats "#\\newline")))

; frequency for 'help.html' file
(file->string file-stats) ; browser 'open' dialog

➛ help.html -> string
➛ (( 28918) (! 138) (# 1035) (#\newline 4539) (#\tab 409) (\$ 7) (% 24) (& 136) (' 1643) ((3577) () 3583) (* 233)
(+ 303) (, 599) (- 3164) (. 1454) (/ 5388) (0 1567) (1 1769) (2 1258) (3 857) (4 1872) (5 453) (6 581) (7 344)
(8 337) (9 411) (: 1235) (; 647) (< 9951) (= 1834) (> 10255) (? 392) (@ 11) (A 166) (B 92) (C 144) (D 72) (E 224)
(F 52) (G 35) (H 42) (I 193) (J 31) (K 36) (L 196) (M 82) (N 94) (O 132) (P 192) (Q 27) (R 56) (S 220) (T 226) (U 37)
(V 51) (W 28) (X 6) (Y 38) (Z 2) ([ 237) (\ 12) (] 215) (^ 28) (_ 107) (` 7) (a 8420) (b 4437) (c 3879) (d 4201)
(e 11905) (f 2989) (g 2068) (h 3856) (i 11313) (j 334) (k 653) (l 5748) (m 3048) (n 7020) (o 7207) (p 3585) (q 249)
(r 8312) (s 8284) (t 8704) (u 3833) (v 1135) (w 861) (x 1172) (y 1451) (z 268) ({ 123) (| 62) (} 123) (~ 7) (§ 1) (© 1)
(« 1) (» 1) (É 2) (à 18) (â 3) (ç 3) (è 6) (é 53) (î 1) (ö 9) (û 1) (œ 1) (ε 2) (λ 12) (μ 1) (ο 2) (ς 1)
(τ 1) (а 1) (д 1) (е 1) (з 1) (л 1) (м 1) (н 1) (я 3) (ἄ 1) (— 2) (“ 2) (” 2) (… 184) (→ 465) (∅ 57) (∈ 4) (∏ 1)
(∑ 2) (∘ 6) (√ 4)(∞ 12) (∫ 2) (⌚ 2) (⌛ 1) (⏳ 4) (☕ 1) (♠ 7) (♡ 2) (♢ 2) (♣ 6) (♤ 2) (♥ 8) (♦ 8)
(♧ 2) (⚁ 1) (⚃ 2) (⚪ 1) (⛔ 1) (✋ 1) (❄ 1) (❅ 1) (❆ 1) (❇ 1) (❈ 1) (❉ 1) (❊ 1) (❋ 1) (❌ 3) (❍ 1)
(❎ 1) (❗ 1) (➛ 900) (➰ 1) (⭕ 2) ... )
➛ Total letters:     212631
➛ Total lines:     4539
```

## Eiffel

```class
APPLICATION

create
make

feature {NONE} -- Initialization

make
-- Read from the file and print frequencies.
local
file: PLAIN_TEXT_FILE
do
file.close
across get_frequencies(file.last_string) as f loop
print(f.key.out + ": " + f.item.out + "%N")
end
end

feature -- Access

get_frequencies (s: STRING): HASH_TABLE[INTEGER, CHARACTER]
-- Hash table of counts for alphabetic characters in `s'.
local
char: CHARACTER
do
create Result.make(0)
across s.area as st loop
char := st.item
if char.is_alpha then
if Result.has(char) then
Result.force(Result.at(char) + 1, char)
else
Result.put (1, char)
end
end
end
end
end
```
Output:
when file contains "Hello, Eiffel world!"
```H: 1
e: 2
l: 4
o: 2
E: 1
i: 1
f: 2
w: 1
r: 1
d: 1```

## Elixir

```file = hd(System.argv)

|> String.upcase
|> String.graphemes
|> Enum.filter(fn c -> c =~ ~r/[A-Z]/ end)
|> Enum.reduce(Map.new, fn c,acc -> Map.update(acc, c, 1, &(&1+1)) end)
|> Enum.sort_by(fn {_k,v} -> -v end)
|> Enum.each(fn {k,v} -> IO.puts "#{k}  #{v}" end)
```
Output:
```C:\Elixir>elixir letterfrequency.exs \work\unixdict.txt
E  20144
A  16421
I  13980
R  13436
T  12836
O  12738
N  12097
S  10210
L  10061
C  8216
U  6489
M  5828
D  5799
P  5516
H  5208
G  4129
B  4115
Y  3633
F  2662
W  1968
K  1925
V  1902
X  617
Z  433
J  430
Q  378
```

## Erlang

```%% Implemented by Arjun Sunel
-module(letter_frequency).
-export([main/0, letter_freq/1]).
main() ->
{ok, FileData} ->
letter_freq(binary_to_list(FileData));
_FileNotExist ->
io:format("File do not exist~n")
end.

letter_freq(Data) ->
lists:foreach(fun(Char) ->
LetterCount = lists:foldl(fun(Element, Count) ->
case Element =:= Char of
true ->
Count+1;
false ->
Count
end
end, 0, Data),

case LetterCount >0 of
true ->
io:format("~p	:	~p~n", [[Char], LetterCount]);
false ->
io:format("")
end
end,  lists:seq(0, 222)).
```
Output:
```"\n"    :       5
" "     :       4
","     :       1
"."     :       22
":"     :       3
"M"     :       1
"a"     :       2
"e"     :       2
"i"     :       1
"j"     :       1
"l"     :       1
"m"     :       1
"n"     :       3
"r"     :       1
"s"     :       2
"u"     :       2
"y"     :       1
"}"     :       2
ok
```

Alternatively letter_freq/1 above can be replaced with

```letter_freq( Data ) ->
Dict = lists:foldl( fun (Char, Dict) -> dict:update_counter( Char, 1, Dict ) end, dict:new(), Data ),
[io:fwrite( "~p	:	~p~n", [[X], dict:fetch(X, Dict)]) || X <- dict:fetch_keys(Dict)].
```

## ERRE

Using ERRE help file for testing.

```PROGRAM LETTER

DIM CNT

BEGIN

OPEN("I",1,"f:\errev30\erre.hlp")

REPEAT
GET(#1,A\$)
L%=LEN(A\$)
IF L%>0 THEN
FOR I%=1 TO L% DO
A%=ASC(MID\$(A\$,I%))
CNT[A%]+=1
END FOR
END IF
UNTIL EOF(1)
CLOSE(1)

FOR C%=\$41 TO \$5A DO
PRINT(CHR\$(C%);CHR\$(C%+32);": ";CNT[C%]+CNT[C%+32])
END FOR

END PROGRAM```

## Euphoria

Works with: OpenEuphoria
```-- LetterFrequency.ex
-- Count frequency of each letter in own source code.

include std/console.e
include std/io.e
include std/text.e

sequence letters = repeat(0,26)

content = lower(content)

for i = 1 to length(content) do
if content[i] > 96 and content[i] < 123 then
letters[content[i]-96] += 1
end if
end for

for i = 1 to 26 do
printf(1,"%s:  %d\n",{i+96,letters[i]})
end for

if getc(0) then end if```
Output:
```a: 4
b: 0
c: 21
-snip
x: 3
y: 3
z: 0
```

## F#

```let alphabet =
['A'..'Z'] |> Set.ofList

let letterFreq (text : string) =
text.ToUpper().ToCharArray()
|> Array.filter (fun x -> alphabet.Contains(x))
|> Seq.countBy (fun x -> x)
|> Seq.sort

let v = "Now is the time for all good men to come to the aid of the party"

let res = letterFreq v

for (letter, freq) in res do
printfn "%A, %A" letter freq
```

## Factor

```USING: hashtables locals io assocs kernel io.encodings.utf8 io.files formatting ;
IN: count-letters

<PRIVATE

: count-from-stream ( -- counts )
52 <hashtable>
[ read1 dup ] [ over inc-at ] while
drop ;

: print-counts ( counts -- )
[ "%c: %d\n" printf ] assoc-each ;

PRIVATE>

: count-letters ( filename -- )
print-counts ;
```

## FBSL

The result of the first evaluation of ASC() is retained in the symbol ASC for later use. This is a standard feature of FBSL functions. The ascii array is dynamic. Command(1) is the name of the script file.

```#APPTYPE CONSOLE

'Open a text file and count the occurrences of each letter.
FUNCTION countBytes(fileName AS STRING)
DIM c AS STRING
DIM ascii[]
DIM handle AS INTEGER = FILEOPEN(fileName, BINARY)
WHILE NOT FILEEOF(handle)
c = FILEGETC(handle)
IF c = "" THEN EXIT WHILE
ascii[ASC] = ascii[ASC(c)] + 1
WEND
FILECLOSE(handle)
RETURN ascii
END SUB

DIM counters = countBytes(COMMAND(1))
FOR DIM i = LBOUND(counters) TO UBOUND(counters)
PRINT i, TAB, IIF(i <= 32, i, CHR(i)), TAB, counters[i]
NEXT

PAUSE
```

## Forth

```create counts 26 cells allot

: freq ( filename -- )
counts 26 cells erase
slurp-file bounds do
i c@ 32 or [char] a -
dup 0 26 within if
cells counts +
1 swap +!
else drop then
loop
26 0 do
cr [char] ' emit  [char] a i + emit  ." ': "
counts i cells + @ .
loop ;

s" example.txt" freq
```

## Fortran

Using the configuration file (which has changed since the example was documented) of the J example, compilation and output of this program on a gnu/linux system is

```-*- mode: compilation; default-directory: "/tmp/" -*-
Compilation started at Sat May 18 18:09:46

a=./F && make \$a && \$a < configuration.file
f95 -Wall -ffree-form F.F -o F
92          21          17          24          82          19          19          22          67           0           2          27          27          57          55          31           1          61          43          60          20           6           2           0          10           0

Compilation finished at Sat May 18 18:09:46
```

And here's the FORTRAN90 program source. The program reads stdin and writes the result to stdout. Future enhancement: use block size records.

```! count letters from stdin
program LetterFrequency
implicit none
character (len=1) :: s
integer, dimension(26) :: a
integer :: ios, i, t
data a/26*0/,i/0/
open(unit=7, file='/dev/stdin', access='direct', form='formatted', recl=1, status='old', iostat=ios)
if (ios .ne. 0) then
write(0,*)'Opening stdin failed'
stop
endif
do i=1, huge(i)
read(unit=7, rec = i, fmt = '(a)', iostat = ios ) s
if (ios .ne. 0) then
!write(0,*)'ios on failure is ',ios
close(unit=7)
exit
endif
t = ior(iachar(s(1:1)), 32) - iachar('a')
if ((0 .le. t) .and. (t .le. iachar('z'))) then
t = t+1
a(t) = a(t) + 1
endif
end do
write(6, *) a
end program LetterFrequency
```

## FreeBASIC

```' FB 1.05.0 Win64

Dim a(65 to 90) As Integer  ' array to hold frequency of each letter, all elements zero initially
Dim fileName As String = "input.txt"
Dim s As String
Dim i As Integer
Open fileName For Input As #1

While Not Eof(1)
Line Input #1, s
s = UCase(s)
For i = 0 To Len(s) - 1
a(s[i]) += 1
Next
Wend

Close #1

Print "The frequency of each letter in the file "; fileName; " is as follows:"
Print
For i = 65 To 90
If a(i) > 0 Then
Print Chr(i); " : "; a(i)
End If
Next
Print
Print "Press any key to quit"
Sleep```
Output:
```/'
results for input.txt which contains the single line:
The quick brown fox jumps over the lazy dog.
'/

The frequency of each letter in the file input.txt is as follows:

A :  1
B :  1
C :  1
D :  1
E :  3
F :  1
G :  1
H :  2
I :  1
J :  1
K :  1
L :  1
M :  1
N :  1
O :  4
P :  1
Q :  1
R :  2
S :  1
T :  2
U :  2
V :  1
W :  1
X :  1
Y :  1
Z :  1
```

Input:

```This is the one question that most people ask. Why bother learning a completely different computing environment, when the operating
system that ships with most desktops, laptops, and servers works just fine? To answer that question, I would pose another question.
Does that operating system you’re currently using really work “just fine”? Or are you constantly battling viruses, malware, slow
downs, crashes, costly repairs, and licensing fees?

If you struggle with the above, and want to free yourself from the constant fear of losing data or having to take your computer in
for the “yearly clean up,” Linux might be the perfect platform for you. Linux has evolved into one of the most reliable computer
ecosystems on the planet. Combine that reliability with zero cost of entry and you have the perfect solution for a desktop platform.
```

## Frink

This example shows some of the subtle and non-obvious power of Frink in processing text files in a language-aware and Unicode-aware fashion:

• Frink has a Unicode-aware function, `graphemeList[str]`, which intelligently enumerates through what a human would consider to be a single visible character, including "characters" composed of multiple Unicode codepoints.
• The file fetched from Project Gutenberg is supposed to be encoded in UTF-8 character encoding, but their servers incorrectly send either that it is Windows-1252 encoded or send no character encoding at all, so this program fixes that.
• Frink has a Unicode-aware lowercase function, `lc[str]` that correctly handles accented characters and may even make a string longer.
• This uses full Unicode tables to determine what is a "letter."
• This works with high Unicode characters, that is above \uFFFF.
• Frink can normalize Unicode characters with its `normalizeUnicode` function so the same grapheme encoded two different ways in Unicode can be treated consistently. For example, a Unicode string can use various methods to encode what is essentially the same character/glyph. For example, the character `ô` can be represented as either `"\u00F4"` or `"\u006F\u0302"`. The former is a "precomposed" character, `"LATIN SMALL LETTER O WITH CIRCUMFLEX"`, and the latter is two Unicode codepoints, an `o` (`LATIN SMALL LETTER O`) followed by `"COMBINING CIRCUMFLEX ACCENT"`. (This is usually referred to as a "decomposed" representation.) Unicode normalization rules can convert these "equivalent" encodings into a canonical representation. This makes two different strings which look equivalent to a human (but are very different in their codepoints) be treated as the same to a computer, and these programs will count them the same. Even if the Project Gutenberg document uses precomposed and decomposed representations for the same characters, this program will fix it and count them the same! See the [Unicode Normal Forms] specification for more about these normalization rules. Frink implements all of them (NFC, NFD, NFKC, NFKD). NFC is the default in `normalizeUnicode[str, encoding=NFC]`. They're interesting!

How many other languages in this page do all or any of this correctly?

`print[formatTable[countToArray[select[graphemeList[lc[normalizeUnicode[read["https://www.gutenberg.org/files/135/135-0.txt", "UTF-8"],"NFC"]]], %r/[[:alpha:]]/ ]] , "right"]]`
Output:
```e 330603
t 235571
a 207101
o 184385
h 176823
i 175320
n 169922
s 162043
r 148632
d 108724
l  99567
u  68295
c  67332
m  62212
w  56507
f  56187
g  48543
p  43366
y  39183
b  37461
v  26258
k  14427
j   5838
x   4026
q   2533
z   1905
é   1473
è    299
æ    116
ê     74
à     64
â     56
ç     50
ü     39
î     39
œ     38
ô     34
ù     18
ï     18
û      9
ë      5
ñ      2
```

## FutureBasic

A clone of the Objective-C solution.

This code assumes a text file named "MyTextFile.txt" is in the same folder as the code file.

```include "NSLog.incl"
include resources "MyTextFile.txt"

void local fn DoIt
CFURLRef      url
CFStringRef   string
NSUInteger    length, index
unichar       chr
CountedSetRef set
CFNumberRef   number

url = fn BundleURLForResource( fn BundleMain, @"MyTextFile", @"txt", NULL )
string = fn StringWithContentsOfURL( url, NSUTF8StringEncoding, NULL )
if ( string )
set = fn CountedSetWithCapacity(0)
length = len(string)
for index = 0 to length - 1
chr = fn StringCharacterAtIndex( string, index )
next
for number in set
NSLog(@"%C = %ld",intVal(number),fn CountedSetCountForObject( set, number ))
next
end if
end fn

fn DoIt

HandleEvents```

## Gambas

```Public Sub Form_Open()
Dim sData As String = File.Load("data.txt")
Dim iCount, iSpaces, iLetters, iOther As Integer
Dim bPunctuation As Boolean

For iCount = 1 To Len(sData)
If InStr("ABCDEFGHIJKLMNOPQRSTUVWXYZ", UCase(Mid(sData, iCount, 1))) Then
Inc iLetters
bPunctuation = True
End If
If Mid(sData, icount, 1) = " " Then
Inc iSpaces
bPunctuation = True
End If
If bPunctuation = False Then Inc iOther
bPunctuation = False
Next

Message("Text contains " & Len(sData) & " characters\n" & iLetters & " Letters\n" & iSpaces & " Spaces\n" & iOther & " Punctuation, newlines etc.")

End```

Output:

```Text contains 854 characters
677 Letters
135 Spaces
42 Punctuation, newlines etc.
```

## Go

```package main

import (
"fmt"
"io/ioutil"
"sort"
"unicode"
)

const file = "unixdict.txt"

func main() {
if err != nil {
fmt.Println(err)
return
}
m := make(map[rune]int)
for _, r := range string(bs) {
m[r]++
}
// answer is now in m.  sort and format output:
lfs := make(lfList, 0, len(m))
for l, f := range m {
lfs = append(lfs, &letterFreq{l, f})
}
sort.Sort(lfs)
fmt.Println("file:", file)
fmt.Println("letter  frequency")
for _, lf := range lfs {
if unicode.IsGraphic(lf.rune) {
fmt.Printf("   %c    %7d\n", lf.rune, lf.freq)
} else {
fmt.Printf("%U  %7d\n", lf.rune, lf.freq)
}
}
}

type letterFreq struct {
rune
freq int
}
type lfList []*letterFreq

func (lfs lfList) Len() int { return len(lfs) }
func (lfs lfList) Less(i, j int) bool {
switch fd := lfs[i].freq - lfs[j].freq; {
case fd < 0:
return false
case fd > 0:
return true
}
return lfs[i].rune < lfs[j].rune
}
func (lfs lfList) Swap(i, j int) {
lfs[i], lfs[j] = lfs[j], lfs[i]
}
```
Output:
```file: unixdict.txt
letter  frequency
U+000A    25104
e      20144
a      16421
i      13980
r      13436
t      12836
o      12738
n      12097
s      10210
l      10061
c       8216
u       6489
m       5828
d       5799
p       5516
h       5208
g       4129
b       4115
y       3633
f       2662
w       1968
k       1925
v       1902
x        617
z        433
j        430
q        378
'        105
&          6
.          6
1          2
0          1
2          1
3          1
4          1
5          1
6          1
7          1
8          1
9          1
```

## Groovy

```def frequency = { it.inject([:]) { map, value -> map[value] = (map[value] ?: 0) + 1; map } }

frequency(new File('frequency.groovy').text).each { key, value ->
println "'\$key': \$value"
}
```
Output:
```'d': 1
'e': 19
'f': 4
' ': 29
'r': 5
'q': 3
'u': 8
[lines omitted]
'o': 2
'x': 1
'h': 1
'k': 2
'"': 2
'\$': 2```

## Harbour

```PROCEDURE Main()
LOCAL s := hb_MemoRead( Left( __FILE__ , At( ".", __FILE__ )) +"prg")
LOCAL c, n, i
LOCAL a := {}

FOR EACH c IN s
IF Asc( c ) > 31
ENDIF
NEXT
a := ASort( a )
i := 1
WHILE i <= Len( a )
c := a[i] ; n := 1
i++
IF i < Len(a) .AND. c == a[i]
WHILE c == a[i]
n++ ; i++
END
ENDIF
?? "'" + c + "'" + "=" + hb_NtoS( n ) + " "
END

RETURN```
Output:
(counting the printable characters of its own source code)
```' '=190 '"'=12 ' ' '=2 '('=10 ')'=10 '+'=12 ','=5 '.'=3 '1'=3 '3'=1 ':'=6 ';'=2 '<'=2 '='=12
'>'=1 '?'=2 'A'=10 'C'=5 'D'=6 'E'=13 'F'=7 'H'=3 'I'=9 'L'=13 'M'=2 'N'=9 'O'=5 'P'=1
'R'=6 'S'=2 'T'=2 'U'=2 'W'=2 'X'=1 '['=3 ']'=3 '_'=10 'a'=12 'b'=2 'c'=9 'd'=3 'e'=5
'f'=1 'g'=1 'h'=2 'i'=11 'm'=1 'n'=7 'o'=3 'p'=1 'r'=2 's'=3 't'=5 'w'=1 '{'=1 '}'=1
```

Short version:

```import Data.List (group,sort)
import Control.Arrow ((&&&))
main = interact (show . map (head &&& length) . group . sort)
```

or, as an alternative to sorting and grouping the whole string, we could use some kind of container as the accumulator for a single fold, for example:

```import Data.List (sortBy)
import qualified Data.Map.Strict as M
import Data.Ord (comparing)

charCounts :: String -> M.Map Char Int
charCounts = foldr (M.alter f) M.empty
where
f (Just x) = Just (succ x)
f _ = Just 1

main :: IO ()
main =
>>= mapM_ print
. sortBy
(flip \$ comparing snd)
. M.toList
. charCounts
```
Output:
```(' ',516452)
('e',325769)
('t',222955)
('a',199774)
('o',180987)
('h',170234)
('n',166901)
('i',165221)
('s',157643)
('r',145136)
('d',106989)
('l',97091)
('\n',73828)
('u',67370)
('c',62760)
('m',56011)
('f',53438)
('w',53332)
(',',48784)
('g',46086)
('p',39958)
('y',37945)
('b',34313)
('.',30487)
('v',24058)
('\8364',21159)
('\226',21155)
('k',14110)
('T',12571)
('I',10067)
('A',7359)
('\339',7121)
('\157',7033)
('H',6605)
('M',6208)
(';',5885)
('E',4969)
('-',4775)
('C',4594)
('S',4404)
('x',3694)
('\8482',3633)
('!',3539)
('R',3535)
('P',3429)
('O',3401)
('j',3392)
('B',3193)
('W',3181)
('\8221',3071)
('N',3053)
('?',2976)
('F',2768)
('G',2512)
(':',2463)
('L',2452)
('J',2448)
('q',2398)
('\195',2296)
('V',2210)
('_',2068)
('z',1847)
('D',1758)
('\169',1328)
('Y',1238)
('U',900)
('1',732)
('8',412)
('X',333)
('K',323)
('\732',298)
('\168',294)
('3',254)
('2',242)
('0',212)
('5',208)
('*',179)
('(',172)
(')',172)
('4',170)
('\8240',146)
('6',143)
('7',140)
('Q',135)
('[',122)
(']',122)
('9',118)
('\166',107)
('\170',74)
('Z',59)
('\162',56)
('\167',48)
('\174',39)
('\197',38)
('"',37)
('\188',37)
('\8220',35)
('\180',34)
('|',24)
('\175',18)
('\185',18)
('/',12)
('\8224',10)
('\187',9)
('\'',8)
('+',5)
('\171',5)
('\710',5)
('\8217',3)
('\$',2)
('\177',2)
('\8225',2)
('#',1)
('%',1)
('&',1)
('@',1)
('{',1)
('}',1)
('\189',1)
('\194',1)```

## Icon and Unicon

The example below counts (case insensitive) letters and was run on a version of this source file.

```link printf

procedure main(A)
every PrintCount(CountLetters(!A))
end

procedure CountLetters(fn)  #: Return case insensitive count of letters
K := table(0)
if f := open(fn,"r") then {
if any(&lcase,c) then K[c] +:= 1
close(f)
return K
}
else write(&errout,"Unable to open file ",fn)
end

procedure PrintCount(T)    #: Print the letters
every c := key(T) do
printf("%s - %d\n",c,T[c])
end
```
Output:
```c - 17
k - 5
s - 10
h - 2
p - 10
e - 41
m - 2
u - 12
b - 2
r - 25
o - 16
w - 1
d - 10
l - 10
t - 27
a - 10
i - 13
y - 5
f - 12
n - 28
v - 4```

## Insitux

Works with the Node REPL.

```(-> (read "README.md")
(filter letter?)
(map upper-case)
freqs
(sort-by 1)
reverse
(map (join " "))
(join "  "))```
Output:
```E 2637  T 2238  R 1893  A 1880  N 1717  I 1676  O 1562  S 1469  L 1156  C 961  U 905  H 699  D 680  P 585  M 567  F 561  G 378  B 373  V 343  Y 324  X 263  W 220  K 134  Z 56  J 49  Q 18
```

## IS-BASIC

```100 PROGRAM "Letters.bas"
110 NUMERIC LETT(65 TO 90)
120 FOR I=65 TO 90
130   LET LETT(I)=0
140 NEXT
150 LET EOF=0
160 OPEN #1:"list.txt"
170 WHEN EXCEPTION USE IOERROR
180   DO
190     GET #1:A\$
200     LET A\$=UCASE\$(A\$)
210     IF A\$>="A" AND A\$<="Z" THEN LET LETT(ORD(A\$))=LETT(ORD(A\$))+1
220   LOOP UNTIL EOF
230 END WHEN
240 FOR I=65 TO 90
250   PRINT CHR\$(I);":";LETT(I),
260 NEXT
270 HANDLER IOERROR
280   LET EOF=-1
290   CLOSE #1
300   CONTINUE
310 END HANDLER```

## J

Input is a directory-path with filename. Result is 26 integers representing counts of each letter, in alphabetic order (a's count is first).

```ltrfreq=: 3 : 0
letters=. u: 65 + i.26  NB. upper case letters
<: #/.~ letters (, -. -.~) toupper fread y
)
```

Example use (based on a configuration file from another task):

```   ltrfreq 'config.file'
88 17 17 24 79 18 19 19 66 0 2 26 26 57 54 31 1 53 43 59 19 6 2 0 8 0
```

## Java

This implementation will capture the frequency of all characters

```import java.io.FileInputStream;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;```
```public static void main(String[] args) throws IOException {
Map<Integer, Integer> frequencies = frequencies("src/LetterFrequency.java");
System.out.println(print(frequencies));
}

static String print(Map<Integer, Integer> frequencies) {
StringBuilder string = new StringBuilder();
int key;
for (Map.Entry<Integer, Integer> entry : frequencies.entrySet()) {
key = entry.getKey();
string.append("%,-8d".formatted(entry.getValue()));
/* display the hexadecimal value for non-printable characters */
if ((key >= 0 && key < 32) || key == 127) {
string.append("%02x%n".formatted(key));
} else {
string.append("%s%n".formatted((char) key));
}
}
return string.toString();
}

static Map<Integer, Integer> frequencies(String path) throws IOException {
/* key = character, and value = occurrences */
Map<Integer, Integer> map = new HashMap<>();
int value;
if (map.containsKey(value)) {
map.put(value, map.get(value) + 1);
} else {
map.put(value, 1);
}
}
return map;
}
}```
```44      0a
463
1       !
8       "
5       %
2       &
33      (
33      )
4       *
1       +
9       ,
3       -
29      .
5       /
2       0
4       1
3       2
1       3
1       7
1       8
1       :
19      ;
7       <
12      =
7       >
2       B
4       E
4       F
2       H
18      I
2       K
2       L
8       M
3       O
3       R
13      S
1       V
1       [
1       ]
73      a
3       b
28      c
19      d
121     e
13      f
25      g
11      h
53      i
6       j
8       k
25      l
22      m
67      n
24      o
44      p
8       q
81      r
30      s
87      t
34      u
15      v
7       w
5       x
20      y
11      {
2       |
11      }
```

Works with: Java version 5+
```import java.io.BufferedReader;
import java.io.IOException;
import java.util.Arrays;

public class LetterFreq {
public static int[] countLetters(String filename) throws IOException{
int[] freqs = new int;
String line;
line = line.toUpperCase();
for(char ch:line.toCharArray()){
if(Character.isLetter(ch)){
freqs[ch - 'A']++;
}
}
}
in.close();
return freqs;
}

public static void main(String[] args) throws IOException{
System.out.println(Arrays.toString(countLetters("filename.txt")));
}
}```
Works with: Java version 7+

In Java 7, we can use try with resources. The `countLetters` method would look like this:

```public static int[] countLetters(String filename) throws IOException{
int[] freqs = new int;
String line;
line = line.toUpperCase();
for(char ch:line.toCharArray()){
if(Character.isLetter(ch)){
freqs[ch - 'A']++;
}
}
}
}
return freqs;
}```
Works with: Java version 8+

In Java 8, we can use streams. This code also handles unicode codepoints as well. The `countLetters` method would look like this:

```public static Map<Integer, Long> countLetters(String filename) throws IOException {
return Files.lines(Paths.get(filename))
.flatMapToInt(String::chars)
.filter(Character::isLetter)
.boxed()
.collect(Collectors.groupingBy(Function.identity(), Collectors.counting()));
}```

## JavaScript

### ES5

JavaScript is no longer used only in environments which are carefully isolated from file systems, but JavaScript standards still do not specify standard file-system functions. Leaving aside the particular and variable details of how files will be opened and read in environments like Node.js and OS X JavaScript for Automation etc., we can still use core JavasScript (ES5 in the example below), to count the characters in a text once it has been read from a file system.

```(function(txt) {

var cs = txt.split(''),
i = cs.length,
dct =  {},
c = '',
keys;

while (i--) {
c = cs[i];
dct[c] = (dct[c] || 0) + 1;
}

keys = Object.keys(dct);
keys.sort();
return keys.map(function (c) { return [c, dct[c]]; });

})("Not all that Mrs. Bennet, however, with the assistance of her five\
daughters, could ask on the subject, was sufficient to draw from her\
husband any satisfactory description of Mr. Bingley. They attacked him\
in various ways--with barefaced questions, ingenious suppositions, and\
distant surmises; but he eluded the skill of them all, and they were at\
last obliged to accept the second-hand intelligence of their neighbour,\
delighted with him. He was quite young, wonderfully handsome, extremely\
agreeable, and, to crown the whole, he meant to be at the next assembly\
with a large party. Nothing could be more delightful! To be fond of\
dancing was a certain step towards falling in love; and very lively\
hopes of Mr. Bingley's heart were entertained.");
```
Output:
```[[" ", 121], ["!", 1], ["'", 1], [",", 13], ["-", 3], [".", 9], [";", 2],
["B", 3], ["H", 2], ["L", 2], ["M", 3], ["N", 2], ["S", 1], ["T", 2], ["W", 1],
["a", 53], ["b", 13], ["c", 17], ["d", 29], ["e", 82], ["f", 17], ["g", 16], ["h", 36],
["i", 44], ["j", 1], ["k", 3], ["l", 34], ["m", 11], ["n", 41], ["o", 40], ["p", 8],
["q", 2], ["r", 35], ["s", 39], ["t", 55], ["u", 20], ["v", 7], ["w", 17], ["x", 2], ["y", 16]]
```

### ES6

Using the 'JavaScript for Automation' embedding of a JSContext on macOS, for access to the file system:

```(() => {
'use strict';

// charCounts :: String -> [(Char, Int)]
const charCounts = s =>
sortBy(flip(comparing(snd)))(
Object.entries(
chars(s).reduce(
(a, c) => (
a[c] = 1 + (a[c] || 0),
a
), {}
)
)
);

// ----------------------- TEST -----------------------
// main :: IO ()
const main = () =>
either(msg => msg)(
compose(
unlines,
map(JSON.stringify),
charCounts
)

// -----------------GENERIC FUNCTIONS -----------------

// Left :: a -> Either a b
const Left = x => ({
type: 'Either',
Left: x
});

// Right :: b -> Either a b
const Right = x => ({
type: 'Either',
Right: x
});

// chars :: String -> [Char]
const chars = s =>
s.split('');

// comparing :: (a -> b) -> (a -> a -> Ordering)
const comparing = f =>
x => y => {
const
a = f(x),
b = f(y);
return a < b ? -1 : (a > b ? 1 : 0);
};

// compose (<<<) :: (b -> c) -> (a -> b) -> a -> c
const compose = (...fs) =>
fs.reduce(
(f, g) => x => f(g(x)),
x => x
);

// either :: (a -> c) -> (b -> c) -> Either a b -> c
const either = fl =>
fr => e => 'Either' === e.type ? (
undefined !== e.Left ? (
fl(e.Left)
) : fr(e.Right)
) : undefined;

// flip :: (a -> b -> c) -> b -> a -> c
const flip = f =>
1 < f.length ? (
(a, b) => f(b, a)
) : (x => y => f(y)(x));

// map :: (a -> b) -> [a] -> [b]
const map = f =>
// The list obtained by applying f
// to each element of xs.
// (The image of xs under f).
xs => (
Array.isArray(xs) ? (
xs
) : xs.split('')
).map(f);

// readFileLR :: FilePath -> Either String IO String
const readFileLR = fp => {
const
e = \$(),
ns = \$.NSString
.stringWithContentsOfFileEncodingError(
\$(fp).stringByStandardizingPath,
\$.NSUTF8StringEncoding,
e
);
return ns.isNil() ? (
Left(ObjC.unwrap(e.localizedDescription))
) : Right(ObjC.unwrap(ns));
};

// snd :: (a, b) -> b
const snd = tpl => tpl;

// sortBy :: (a -> a -> Ordering) -> [a] -> [a]
const sortBy = f =>
xs => xs.slice()
.sort((a, b) => f(a)(b));

// unlines :: [String] -> String
const unlines = xs =>
// A single string formed by the intercalation
// of a list of strings with the newline character.
xs.join('\n');

// MAIN ---
return main();
})();
```
Output:
```[" ",516452]
["e",325769]
["t",222955]
["a",199774]
["o",180987]
["h",170234]
["n",166901]
["i",165221]
["s",157643]
["r",145136]
["d",106989]
["l",97091]
["\n",73828]
["u",67370]
["c",62760]
["m",56011]
["f",53438]
["w",53332]
[",",48784]
["g",46086]
["p",39958]
["y",37945]
["b",34313]
[".",30487]
["v",24058]
["€",21159]
["â",21155]
["k",14110]
["T",12571]
["I",10067]
["A",7359]
["œ",7121]
["�",7033]
["H",6605]
["M",6208]
[";",5885]
["E",4969]
["-",4775]
["C",4594]
["S",4404]
["x",3694]
["™",3633]
["!",3539]
["R",3535]
["P",3429]
["O",3401]
["j",3392]
["B",3193]
["W",3181]
["”",3071]
["N",3053]
["?",2976]
["F",2768]
["G",2512]
[":",2463]
["L",2452]
["J",2448]
["q",2398]
["Ã",2296]
["V",2210]
["_",2068]
["z",1847]
["D",1758]
["Y",1238]
["U",900]
["1",732]
["8",412]
["X",333]
["K",323]
["˜",298]
["¨",294]
["3",254]
["2",242]
["0",212]
["5",208]
["*",179]
["(",172]
[")",172]
["4",170]
["‰",146]
["6",143]
["7",140]
["Q",135]
["[",122]
["]",122]
["9",118]
["¦",107]
["ª",74]
["Z",59]
["¢",56]
["§",48]
["®",39]
["Å",38]
["¼",37]
["\"",37]
["“",35]
["´",34]
["|",24]
["¯",18]
["¹",18]
["/",12]
["†",10]
["»",9]
["'",8]
["ˆ",5]
["«",5]
["+",5]
["’",3]
["±",2]
["‡",2]
["\$",2]
["#",1]
["&",1]
["Â",1]
["½",1]
["{",1]
["}",1]
["%",1]
["@",1]```

Or, using an object as a hash-table, and the reduce method: (note that this version omits the opening of a text file which is specified in the task description):

```(() => {
'use strict';

const letterfreq = text => [...text]
.reduce(
(a, c) => (a[c] = (a[c] || 0) + 1, a),
{}
);

return JSON.stringify(
letterfreq(
`remember, remember, the fifth of november
gunpowder treason and plot
I see no reason why gunpowder treason
should ever be forgot`
),
null, 2
);
})();
```

Using the spread operator, you get the unicode characters rather than the UTF-16 code units.

Output:
```{
"r": 12,
"e": 19,
"m": 5,
"b": 4,
",": 2,
" ": 56,
"t": 6,
"h": 4,
"f": 4,
"i": 1,
"o": 12,
"n": 8,
"v": 2,
"\n": 3,
"g": 3,
"u": 3,
"p": 3,
"w": 3,
"d": 4,
"a": 4,
"s": 5,
"l": 2,
"I": 1,
"y": 1
}```

## jq

The following program will report the frequency of all characters in the input file, including newlines, returns, etc, provided the file will fit in memory.
```# Input: an array of strings.
# Output: an object with the strings as keys,
# the values of which are the corresponding frequencies.
def counter:
reduce .[] as \$item ( {}; .[\$item] += 1 ) ;

# For neatness we sort the keys:
explode | map( [.] | implode ) | counter | . as \$counter
| keys | sort[] | [., \$counter[.] ]```
Example:
```jq -s -R -c -f Letter_frequency.jq somefile.txt
```
Output:
```["\n",12]
[" ",124]
["#",1]
["\$",8]
["(",4]
[")",4]
["+",3]
[",",4]
["-",4]
[".",9]
["0",3]
["1",7]
[":",2]
[";",2]
["=",4]
...```

## Julia

```using DataStructures

function letterfreq(file::AbstractString; fltr::Function=(_) -> true)
end

display(letterfreq("src/Letter_frequency.jl"; fltr=isletter))
```
Output:
```DataStructures.OrderedDict{Char,Int64} with 29 entries:
'A' => 1
'C' => 1
'D' => 2
'F' => 1
'L' => 3
'S' => 2
'a' => 9
'b' => 1
'c' => 13
'd' => 5
'e' => 30
'f' => 13
'g' => 4
'h' => 10
'i' => 14
'j' => 1
'k' => 3
'l' => 11
'n' => 15
⋮   => ⋮
```

## K

```+(?a;#:'=a:,/0:`)
```

Example: The file "hello.txt" contains the string "Hello, world!"

```
c:+(?a;#:'=a:,/0:`hello.txt)
```
Output:
```(("H";1)
("e";1)
("l";3)
("o";2)
(",";1)
(" ";1)
("w";1)
("r";1)
("d";1)
("!";1))
```

Sort on decreasing occurrences:

```     c@>c[;1]
```
Output:
```(("l";3)
("o";2)
("H";1)
("e";1)
(",";1)
(" ";1)
("w";1)
("r";1)
("d";1)
("!";1))
```

## Kotlin

```// version 1.1.2

import java.io.File

fun main(args: Array<String>) {
val letterMap = text.filter { it in 'a'..'z' }.groupBy { it }.toSortedMap()
for (letter in letterMap) println("\${letter.key} = \${letter.value.size}")
val sum = letterMap.values.sumBy { it.size }
println("\nTotal letters = \$sum")
}
```
Output:

'input.txt' just contains two pangrams:

The quick brown fox jumps over the lazy dog. Sphinx of black quartz, judge my vow.

```a = 3
b = 2
c = 2
d = 2
e = 4
f = 2
g = 2
h = 3
i = 2
j = 2
k = 2
l = 2
m = 2
n = 2
o = 6
p = 2
q = 2
r = 3
s = 2
t = 3
u = 4
v = 2
w = 2
x = 2
y = 2
z = 2

Total letters = 64
```

## Ksh

```#!/bin/ksh

# Count the occurrences of each character

######
# main #
######

typeset -iA freqCnt
done
done < \$0		## Count chars of this code file

for ch in "\${!freqCnt[@]}"; do
[[ \${ch} == ?(\S) ]] && print -- "\${ch}  \${freqCnt[\${ch}]}"
done
```
Output:

Counts the characters of the source code file

```!  2
"  4
#  19
\$  8
&  2
(  5
)  5
+  4
-  3
/  2
0  2
1  1
:  2
;  5
<  2
=  3
?  1
@  1
A  1
C  6
E  2
L  2
P  2
R  2
S  1
Y  2
[  5
]  5
a  6
b  1
c  12
d  8
e  18
f  9
h  11
i  12
k  1
l  2
m  1
n  14
o  14
p  2
q  4
r  13
s  5
t  12
u  3
w  1
y  1
{  7
```

## Lambdatalk

In this entry we choose to show how lambdatalk can use any existing javascript code (say the #Javascript entry in this page), and build an interface to use it as a standard lambdatalk function. So, applied to any string the W.frequency primitive returns a pair structure containing the array of chars and the corresponding array of frequencies.

```{script
// W.frequency is added to the lambdatalk dictionary via the {script ...} special form

LAMBDATALK.DICT['W.frequency'] = function() {

// 1) simply copied from the rosetta.org #Javascript entry
var frequency = function(txt) {
var cs  = txt.split(''),
i = cs.length,
dct = {},
c = '';
while (i--) {
c = cs[i];
dct[c] = (dct[c] || 0) + 1;
}
var keys = Object.keys(dct);
keys.sort();
return keys.map(function (c) { return [c, dct[c]]; });
};

// 2) then interfaced with lambdatalk
var args = arguments.trim().replace( /\s+/g, "␣" );

var output = frequency( args );

for (var a=[], b=[], i=0; i< output.length; i++) {
a.push( output[i] );
b.push( output[i] );
}

var pair = "{cons {A.new " + a.join(" ") +
"} {A.new " + b.join(" ") + "}}"

return LAMBDATALK.eval_forms( pair );
};
}

{def S3
Not all that Mrs. Bennet, however, with the assistance of her five daughters, could ask on the subject, was sufficient to draw from her husband any satisfactory description of Mr. Bingley. They attacked him in various ways--with barefaced questions, ingenious suppositions, and distant surmises; but he eluded the skill of them all, and they were at last obliged to accept the second-hand intelligence of their neighbour, Lady Lucas. Her report was highly favourable. Sir William had been delighted with him. He was quite young, wonderfully handsome, extremely agreeable, and, to crown the whole, he meant to be at the next assembly with a large party. Nothing could be more delightful! To be fond of dancing was a certain step towards falling in love; and very lively hopes of Mr. Bingley's heart were entertained.
}
-> S3
{def S3.freq {W.frequency {S3}}}
-> S3.freq

characters:  {car {S3.freq}}
->  [!,',,,-,.,;,B,H,L,M,N,S,T,W,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,␣]

frequencies: {cdr {S3.freq}}
-> [1,1,13,3,9,2,3,2,2,3,2,1,2,1,53,13,17,29,82,17,16,36,44,1,3,34,11,41,40,8,2,35,39,55,20,7,17,2,16,132]
}
```

## langur

Works with: langur version 0.7.0
```val .countLetters = f(.s) {
for[=h{}] .s2 in split(replace(.s, RE/\P{L}/)) {
_for[.s2; 0] += 1
}
}

writeln join "\n", map f(.k) \$"\.k;: \.counts[.k];", keys .counts```
Output:

The input contains "fuzzy furry kittens ασδ ξκλ ασδ ξα" (random Greek letters at the end) and the output is as follows.

```f: 2
u: 2
z: 2
y: 2
r: 2
k: 1
i: 1
t: 2
e: 1
n: 1
s: 1
α: 3
σ: 2
δ: 2
ξ: 2
κ: 1
λ: 1
```

## Lasso

```local(
str 	= 'Hello world!',
freq	= map
)
// as a loop. arguably quicker than query expression
loop(#str->size) => {
#freq->keys !>> #str->get(loop_count) ?
#freq->insert(#str->get(loop_count) = #str->values->find(#str->get(loop_count))->size)
}

// or
local(
str 	= 'Hello world!',
freq	= map
)
// as query expression, less code
with i in #str->values where #freq->keys !>> #i do => {
#freq->insert(#i = #str->values->find(#i)->size)
}

// output #freq
with elem in #freq->keys do => {^
'"'+#elem+'": '+#freq->find(#elem)+'\r'
^}
```

## Liberty BASIC

Un-rem a line to convert to all-upper-case. Letter freq'y is printed as percentages.

```    open "text.txt" for input as #i
txt\$ =input\$( #i, lof( #i))
Le =len( txt\$)
close #i

dim LetterFreqy( 255)

'   txt\$ =upper\$( txt\$)

for i =1 to Le
char =asc( mid\$( txt\$, i, 1))
if char >=32 then LetterFreqy( char) =LetterFreqy( char) +1
next i

for j =32 to 255
if LetterFreqy( j) <>0 then print " Character #"; j, "("; chr\$( j);_
") appeared "; using( "##.##", 100 *LetterFreqy( j) /Le); "% of the time."
next j

end```

## Lua

This solution counts letters only, which could be changed by altering the pattern argument to 'gmatch' on line 31. It also treats upper and lower case letters as distinct, which could be changed by changing everything to upper or lower case with string.upper() or string.lower() before tallying.

```-- Return entire contents of named file
local file = assert(io.open(filename, "r"))
file:close()
return contents
end

-- Return a closure to keep track of letter counts
function tally ()
local t = {}

-- Add x to tally if supplied, return tally list otherwise
local function count (x)
if x then
if t[x] then
t[x] = t[x] + 1
else
t[x] = 1
end
else
return t
end
end

return count
end

-- Main procedure
local letterCount = tally()
for letter in readFile(arg or arg):gmatch("%a") do
letterCount(letter)
end
for k, v in pairs(letterCount()) do
print(k, v)
end
```

Output from running this script on itself:

```i       24
f       16
R       2
v       2
c       19
k       4
M       1
s       14
d       17
l       40
e       61
t       54
m       4
r       34
u       18
C       3
o       32
A       1
g       3
x       7
F       2
y       4
w       1
n       42
h       4
a       25
p       7```

## M2000 Interpreter

```document file1\$={Open a text file and count the occurrences of each letter.
Some of these programs count all characters (including punctuation), but some only count letters A to Z
}
const Ansi=3, nl\$=chr\$(13)+chr\$(10), Console=-2
save.doc file1\$, "checkdoc.txt", Ansi
open "checkdoc.txt" for input as F
buffer onechar as byte
m=0
dim m(65 to 90)
while not eof(#F)
get #F, onechar
a\$=chr\$(eval(onechar,0))
if a\$ ~ "[A-Za-z]" then
m++
m(asc(ucase\$(a\$)))++
end if
end while
close #F
document Export\$
for i=65 to 90
if m(i)>0 then Export\$=format\$("{0} - {1:2:4}%",chr\$(i),m(i)/m*100)+nl\$
next
print #Console, Export\$
clipboard Export\$```
Output:
```A - 6,87%
B - 0,76%
C - 8,40%
D - 1,53%
E - 12,2%
F - 2,29%
G - 1,53%
H - 3,05%
I - 3,05%
L - 5,34%
M - 2,29%
N - 8,40%
O - 9,92%
P - 2,29%
R - 6,11%
S - 5,34%
T - 12,2%
U - 6,11%
X - 0,76%
Y - 0,76%
Z - 0,76%
```

## Maple

`StringTools:-CharacterFrequencies(readbytes("File.txt",infinity,TEXT))`

## Mathematica / Wolfram Language

```Tally[Characters[Import["file.txt","Text"]]]
```

## MATLAB / Octave

```function u = letter_frequency(t)
if ischar(t)
t = abs(t);
end;
A = sparse(t+1,1,1,256,1);
printf('"%c":%i\n',[find(A)-1,A(A>0)]')
end
```

## Nanoquery

```// define a list to hold characters and amounts
characters = list()
amounts = list()

// define the alphabet as a string to check only letters and numbers
alpha = "abcdefghijklmnopqrstuvwxyz0123456789"

// get the filename as an argument
fname = args[len(args) - 1]

// read the entire file into a string

// loop through all the characters in the array
for i in range(0, len(contents) - 1)
// get the character to check
toCheck = str(contents[i]).toLowerCase()

// check if the current character is in the array
if ((alpha .contains. toCheck) && (characters .contains. toCheck))
// if it's there, increment its amount
index = characters[toCheck]
amounts[index] = amounts[index] + 1
else
if (alpha .contains. toCheck)
// if it's not, add it
append characters toCheck
append amounts 0
end
end if
end for

// output the amounts
println format("%-20s %s", "Character", "Amount")
println "=" * 30
for i in range(0, len(characters) - 1)
println format("%-20s %d", characters[i], amounts[i])
end for```
Output:
```\$ java -jar ../nanoquery-2.3_1462.jar -b letterfreq.nq sherlock-holmes.txt
Character            Amount
==============================
p                    7239
r                    25708
o                    34866
j                    544
e                    54972
c                    11118
t                    40545
g                    8311
u                    13604
n                    29701
b                    6645
s                    27941
h                    29588
a                    36146
d                    19064
v                    4567
f                    9362
l                    17633
k                    3684
m                    12150
y                    9776
i                    31240
w                    11554
2                    45
9                    23
0                    104
1                    127
6                    30
8                    46
z                    152
x                    578
q                    437
5                    27
4                    29
7                    25
3                    25```

## NetRexx

Translation of: REXX
```/* NetRexx ************************************************************
* 22.05.2013 Walter Pachl  translated from REXX
**********************************************************************/
options replace format comments java crossref symbols nobinary

parse arg dsn .
if dsn = '' then
dsn = 'test.txt'
cnt=0
totChars=0                         /*count of the total num of chars*/
totLetters=0                       /*count of the total num letters.*/
indent=' '.left(20)                /*used for indentation of output.*/
lines = scanFile(dsn)
loop l_ = 1 to lines
line = lines[l_]

Say '>'line'<' line.length       /* that's in test.txt            */
/*
lrx=left_right(line)
Parse lrx leftx rightx
Say ' 'leftx
Say ' 'rightx
*/
loop k=1 for line.length()       /*loop over characters           */
totChars=totChars+1            /*Increment total number of chars*/
c=line.substr(k,1)             /*get character number k         */
cnt[c]=cnt[c]+1                /*increment the character's count*/
End
end l_

w=totChars.length                  /*used for right-aligning counts.*/
say 'file -----' dsn "----- has" lines 'records.'
say 'file -----' dsn "----- has" totChars 'characters.'
Loop L=0 to 255                    /* display nonzero letter counts */
c=l.d2c                          /* the character in question     */
if cnt[c]>0 & c.datatype('M')>0 Then Do /* was found in the file  */
/* and is a latin letter         */
say indent "(Latin) letter " c 'count:' cnt[c].right(w) /* tell */
totLetters=totLetters+cnt[c]   /* increment number of letters   */
End
End

say 'file -----' dsn "----- has" totLetters '(Latin) letters.'
say '                           other charactes follow'
other=0
loop m=0 to 255                    /* now for non-letters           */
c=m.d2c                          /* the character in question     */
y=c.c2x                          /* the hex representation        */
if cnt[c]>0 & c.datatype('M')=0 Then Do /* was found in the file  */
/* and is not a latin letter     */
other=other+cnt[c]             /* increment count               */
_=cnt[c].right(w)              /* prepare output of count       */
select                         /*make the character viewable.   */
when c<<' ' | m==255 then say indent "'"y"'x character count:" _
when c==' '          then say indent "blank character count:" _
otherwise                 say indent "   " c 'character count:' _
end
end
end
say 'file -----' dsn "----- has" other 'other characters.'
say 'file -----' dsn "----- has" totLetters 'letters.'

-- Read a file and return contents as a Rexx indexed string
method scanFile(dsn) public static returns Rexx

fileLines = ''
do
inFile = File(dsn)
inFileScanner = Scanner(inFile)
loop l_ = 1 while inFileScanner.hasNext()
fileLines = l_
fileLines[l_] = inFileScanner.nextLine()
end l_
inFileScanner.close()

catch ex = FileNotFoundException
ex.printStackTrace
end

return fileLines```

## Nim

```import tables, os

var t = initCountTable[char]()
for l in paramStr(1).lines:
for c in l:
t.inc(c)
echo t
```

## Objeck

```use IO;

bundle Default {
class Test {
function : Main(args : String[]) ~ Nil {
freqs := CountLetters("filename.txt");
for(i := 'A'; i < 'Z'; i += 1;) {
Console->Print(i->As(Char))->Print("=>")->PrintLine(freqs[i - 'A']);
};
}

function : CountLetters(filename : String) ~ Int[] {
freqs := Int->New;
each(i : line) {
ch := line->Get(i);
if(ch->IsChar()){
index := ch - 'A';
freqs[index] := freqs[index] + 1;
};
};
};

return freqs;
}
}
}```

## Objective-C

```#import <Foundation/Foundation.h>

int main (int argc, const char *argv[]) {
@autoreleasepool {

NSData *data = [NSData dataWithContentsOfFile:@(argv)];
NSString *string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSCountedSet *countedSet = [[NSCountedSet alloc] init];
NSUInteger len = [string length];
for (NSUInteger i = 0; i < len; i++) {
unichar c = [string characterAtIndex:i];
if ([[NSCharacterSet letterCharacterSet] characterIsMember:c])
}
for (NSNumber *chr in countedSet) {
NSLog(@"%C => %lu", (unichar)[chr integerValue], [countedSet countForObject:chr]);
}

}
return 0;
}
```

## OCaml

We open a text file and compute letter frequency. Other characters than [a-z] and [A-Z] are ignored, and upper case letters are first converted to lower case before to compute letter frequency.

```let () =
let ic = open_in Sys.argv.(1) in
let base = int_of_char 'a' in
let arr = Array.make 26 0 in
try while true do
let c = Char.lowercase(input_char ic) in
let ndx = int_of_char c - base in
if ndx < 26 && ndx >= 0 then
arr.(ndx) <- succ arr.(ndx)
done
with End_of_file ->
close_in ic;
for i=0 to 25 do
Printf.printf "%c -> %d\n" (char_of_int(i + base)) arr.(i)
done
```

If we want to compute all characters in an UTF8 file, we must use an external library, for example Batteries. The following function takes as input a string that contains the path to the file, and prints all the characters together with their frequencies, ordered by increasing frequencies, on the standard output.

```open Batteries

let frequency file =
let freq = Hashtbl.create 52 in
File.with_file_in file
(Enum.iter (fun c -> Hashtbl.modify_def 1 c succ freq) % Text.chars_of);
List.iter (fun (k,v) -> Text.write_text stdout k;
Printf.printf " %d\n" v)
@@ List.sort (fun (_,v) (_,v') -> compare v v')
@@ Hashtbl.fold (fun k v l -> (Text.of_uchar k,v) :: l) freq []
```

## Ol

```(define source (bytes->string (file->bytestream "letter_frequency.scm"))) ; utf-8
(define dict (lfold (lambda (ff char)
(put ff char (+ 1 (get ff char 0))))
{}
(str-iter source)))
; that's all.

; just print the dictionary in human readable format:
(for-each (lambda (kv)
(let* ((key value kv))
(case key
(#\newline
(display "NEWLINE"))
(#\tab
(display "TAB"))
(#\space
(display "SPACE"))
((< key #\space) => (lambda (_)
(display "char ") (display key)))
(else
(display (string key))))
(display " --> ")
(display value))
(print))
(ff->alist dict))
```
Output:
```NEWLINE --> 27
SPACE --> 374
" --> 12
# --> 5
' --> 1
( --> 37
) --> 37
* --> 1
+ --> 1
- --> 8
. --> 3
/ --> 4
0 --> 1
1 --> 1
8 --> 1
: --> 2
; --> 4
< --> 1
= --> 1
> --> 5
A --> 2
B --> 1
C --> 1
E --> 3
I --> 1
L --> 2
N --> 2
O --> 1
P --> 1
S --> 1
T --> 1
W --> 1
\ --> 4
_ --> 3
a --> 35
b --> 7
c --> 17
d --> 19
e --> 41
f --> 17
g --> 4
h --> 9
i --> 25
j --> 1
k --> 8
l --> 25
m --> 7
n --> 13
o --> 9
p --> 14
q --> 2
r --> 23
s --> 24
t --> 31
u --> 10
v --> 4
w --> 2
y --> 18
{ --> 1
} --> 1
```

## OxygenBasic

```indexbase 0

sys a,e,i,c

string s=getfile "t.txt"

e=len s

for i=1 to e
a=asc(s,i)
++c(a)
next

cr=chr(13)+chr(10)
pr="Char Frequencies" cr cr
for i=32 to 255
pr+=chr(i) chr(9) c(i) cr
next

print pr
'putfile "CharCount.txt",pr```

## PARI/GP

```v=vector(26);
for(i=1,#U,u=Vecsmall(U[i]);for(j=1,#u,if(u[j]>64&&u[j]<91,v[u[j]-64]++,u[j]>96&&u[j]<123,v[u[j]-96]++)));
v```

## Pascal

Works with: Extended Pascal
```program letterFrequency(input, output);
var
chart: array[char] of 0..maxInt value [otherwise 0];
c: char;
begin
{ parameter-less EOF checks for EOF(input) }
while not EOF do
begin
chart[c] := chart[c] + 1
end;

{ now, chart[someLetter] gives you the letter’s frequency }
end.
```

## Perl

Counts letters in files given on command line or piped to stdin. Case insensitive.

```while (<>) { \$cnt{lc chop}++ while length }
print "\$_: ", \$cnt{\$_}//0, "\n" for 'a' .. 'z';
```

## Phix

Counts own source or supplied filename Now counts words in unixdict.txt of 17 letters or more (to make it js compatible)

```with javascript_semantics
sequence lc = repeat(0,#7E)
--string text = get_text(command_line()[\$])
string text = join(unix_dict(17))
for i=1 to length(text) do
integer ch = text[i]
if ch=-1 then exit end if
if ch>=' ' and ch<#7F then
lc[ch] += 1
end if
end for

integer count = 0
for i=' ' to #7E do
if lc[i]!=0 then
count = mod(count+1,10)
printf(1,"'%c': %-2d%s",{i,lc[i],iff(count=0?"\n":"  ")})
end if
end for
```
Output:
```' ': 14  'a': 15  'b': 2   'c': 20  'd': 7   'e': 33  'g': 7   'h': 16  'i': 22  'l': 16
'm': 5   'n': 14  'o': 27  'p': 15  'r': 26  's': 15  't': 24  'u': 6   'v': 1   'y': 4
```

## Phixmonti

```0 255 repeat var ascCodes

"unixdict.txt" "r" fopen var file

file 0 < not
if
true
while
file fgets
dup 0 < not
if
len 1 swap 2 tolist
for
var i
i get ascCodes over get 1 + rot set var ascCodes
endfor
drop
true
else
drop
false
endif
endwhile

ascCodes len
for
var i
i get
if
i tochar print " = " print i get print nl
endif
endfor
file fclose
endif```

## PHP

```<?php
print_r(array_count_values(str_split(file_get_contents(\$argv))));
?>
```

## Picat

Sorting on the frequency (decreasing).

```go =>
% removing '\n' first
M = letter_freq(Chars),
println(M.sort_map(values).reverse).

% Get the letter frequency
letter_freq(S) = Map =>
Map = new_map(),
foreach(C in S)
Map.put(C,Map.get(C,0)+1)
end.

% Different sorting function on maps
sort_map(Map,values) = [K=V:_=(K=V) in sort([V=(K=V): K=V in Map])].
sort_map(Map,keys)   = sort([KV : KV in Map]).
sort_map(Map)        = sort_map(Map,keys).```
Output:
```[e = 20144,a = 16421,i = 13980,r = 13436,t = 12836,o = 12738,n = 12097,s = 10210,
l = 10061,c = 8216,u = 6489,m = 5828,d = 5799,p = 5516,h = 5208,g = 4129,b = 4115,
y = 3633,f = 2662,w = 1968,k = 1925,v = 1902,x = 617,z = 433,j = 430,q = 378,
' = 105,. = 6,& = 6,1 = 2,9 = 1,8 = 1,7 = 1,6 = 1,5 = 1,4 = 1,3 = 1,2 = 1,0 = 1]```

## PicoLisp

```(let Freq NIL
(in "file.txt"
(while (char) (accu 'Freq @ 1)) )
(sort Freq) )```

For a "file.txt":

```abcd
cdef```
Output:
`-> (("^J" . 2) ("a" . 1) ("b" . 1) ("c" . 2) ("d" . 2) ("e" . 1) ("f" . 1))`

## Pike

```string all = Stdio.read_file("README.md");
mapping res = ([]);
foreach(all/1, string char)
res[char]++;
write("%O\n", res);
```
Output:
```([ /* 26 elements */
"\n": 2,
" ": 12,
".": 2,
"/": 3,
":": 1,
"P": 1,
"T": 1,
"a": 5,
"c": 1,
"d": 2,
"e": 10,
"f": 3,
"g": 1,
"h": 2,
"i": 5,
"k": 1,
"l": 4,
"m": 3,
"n": 1,
"o": 7,
"p": 4,
"r": 4,
"s": 10,
"t": 5,
"u": 2,
"x": 2
])
```

## PL/I

```frequencies: procedure options (main);
declare tallies(26) fixed binary static initial ((26) 0);
declare alphabet character (26) static initial
('ABCDEFGHIJKLMNOPQRSTUVWXYZ');
declare c character (1), i fixed binary;
declare in file;

open file (in) title ('/LETTER.DAT,type(text),recsize(200)') input;

on endfile (in) go to prepare_list;

do while('1'b);
get file (in) edit (c) (a(1)); put edit (c) (a);
i = index(alphabet, c);
if i > 0 then tallies(i) = tallies(i) + 1;
end;

prepare_list:
put skip list('Letter', 'Frequency');
do i = 1 to 26;
if tallies(i) > 0 then
put skip list (substr(alphabet, i, 1), tallies(i));
end;
end frequencies;```

Data:

```THEQUICKBROWNFOX
JUMPSOVERTHELAZYDOG
```
Output:
```Letter                  Frequency
A                               1
B                               1
C                               1
D                               1
E                               3
F                               1
G                               1
H                               2
I                               1
J                               1
K                               1
L                               1
M                               1
N                               1
O                               4
P                               1
Q                               1
R                               2
S                               1
T                               2
U                               2
V                               1
W                               1
X                               1
Y                               1
Z                               1
```

## PowerShell

```function frequency (\$string) {
\$arr = \$string.ToUpper().ToCharArray() |where{\$_ -match '[A-KL-Z]'}
\$n = \$arr.count
\$arr | group | foreach{
[pscustomobject]@{letter = "\$(\$_.name)"; frequency  = "\$([math]::round(\$(\$_.Count/\$n),5))"; count = "\$(\$_.count)"}
} | sort letter
}
\$file = "\$(\$MyInvocation.MyCommand.Name )" #Put the name of your file here
frequency \$(get-content \$file -Raw)
```

Output:

```letter frequency count
------ --------- -----
A      0.06809   16
B      0.00426   1
C      0.06809   16
D      0.00851   2
E      0.11064   26
F      0.0383    9
G      0.01702   4
H      0.02979   7
I      0.03404   8
J      0.00426   1
K      0.00426   1
L      0.02553   6
M      0.04255   10
N      0.09362   22
O      0.08085   19
P      0.02128   5
Q      0.01277   3
R      0.10638   25
S      0.02128   5
T      0.10213   24
U      0.05957   14
V      0.00426   1
W      0.00851   2
Y      0.02979   7
Z      0.00426   1
```

## Prolog

Works with SWI-Prolog.
Only alphabetic codes are computed in uppercase state.
Uses packlist/2 defined there : Run-length encoding#Prolog

```frequency(File) :-

% we only keep alphabetic codes
include(my_code_type, Code, LstCharCode),

% we translate char_codes into uppercase atoms.
maplist(my_upcase, LstCharCode, LstChar),

% sort and pack the list
msort(LstChar, SortLstChar),
packList(SortLstChar, Freq),
maplist(my_write, Freq).

my_write([Num, Atom]) :-
swritef(A, '%3r', [Num]),
writef('Number of %w :%w\n', [Atom, A]).

my_code_type(Code) :-
code_type(Code, alpha).

my_upcase(CharCode, UpChar) :-
char_code(Atom, CharCode),
upcase_atom(Atom, UpChar).

:- use_module(library(clpfd)).
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% ?- packList([a,a,a,b,c,c,c,d,d,e], L).
%  L = [[3,a],[1,b],[3,c],[2,d],[1,e]] .
%
% ?- packList(R,  [[3,a],[1,b],[3,c],[2,d],[1,e]]).
% R = [a,a,a,b,c,c,c,d,d,e] .
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
packList([],[]).

packList([X],[[1,X]]) :-
!.

packList([X|Rest],[XRun|Packed]):-
run(X,Rest, XRun,RRest),
packList(RRest,Packed).

run(Var,[],[1,Var],[]).

run(Var,[Var|LRest],[N1, Var],RRest):-
N #> 0,
N1 #= N + 1,
run(Var,LRest,[N, Var],RRest).

run(Var,[Other|RRest], [1,Var],[Other|RRest]):-
dif(Var,Other).
```
Output:
for this file
```Number of A : 63
Number of B :  7
Number of C : 53
Number of D : 29
Number of E : 65
...
Number of T : 52
Number of U : 20
Number of V : 10
Number of W :  8
Number of X :  6
Number of Y : 12
true .
```

## PureBasic

Alphabetic codes are converted to uppercase before being used and no other codes are used as part of the calculations.

```Procedure countLetters(Array letterCounts(1), textLine.s)
;counts only letters A -> Z, uses index 0 of letterCounts() to keep a total of all counts
Protected i, lineLength = Len(textLine), letter

textLine = UCase(textLine)
For i = 1 To lineLength
letter = Asc(Mid(textLine, i, 1)) - 'A' + 1
If letter >= 1 And letter <= 26
letterCounts(letter) + 1 ;tally individual letter count
letterCounts(0) + 1      ;increment total letter count
EndIf
Next
EndProcedure

If OpenConsole()
Define filename.s, fileID, i
filename = OpenFileRequester("Select text file to examine", "*.txt", "Text (*.txt)|*.txt;|All files (*.*)|*.*", 0)
fileID = 0
Dim letterCounts(26) ;A - Z only, index 0 contains the total of all letter counts

Define textLine.s
While Not Eof(fileID)
countLetters(letterCounts(), textLine)
Wend
CloseFile(fileID)

PrintN("File: " + filename + #CRLF\$)
PrintN("Letter  %Freq  Count")
For i = 1 To 26
Print("  " + Chr(64 + i) + "     ")
Print(RSet(StrF(100 * letterCounts(i) / letterCounts(0), 1), 5, " ") + "  ")
PrintN(Str(letterCounts(i)))
Next
PrintN(#CRLF\$ + "Total letter count in file: " + Str(letterCounts(0)))
EndIf

Print(#CRLF\$ + #CRLF\$ + "Press ENTER to exit"): Input()
CloseConsole()
EndIf```
Output:
```File: D:\_T\Text\dictionary.txt

Letter  %Freq  Count
A       7.6  27743
B       2.0  7248
C       4.3  15433
D       3.8  13798
E      11.8  42917
F       1.4  5030
G       2.8  10336
H       2.1  7720
I       8.6  31141
J       0.2  588
K       0.8  2964
L       5.3  19399
M       2.7  9821
N       7.1  25682
O       6.1  22084
P       2.9  10696
Q       0.2  714
R       7.5  27055
S       8.0  28898
T       7.1  25773
U       3.3  12032
V       1.1  4019
W       0.9  3348
X       0.3  1096
Y       1.7  6251
Z       0.3  1177

Total letter count in file: 362963```

## Python

### Functional

#### Using collections.Counter

Works with: Python version 2.7+ and 3.1+
```import collections, sys

def filecharcount(openfile):
return sorted(collections.Counter(c for l in openfile for c in l).items())

f = open(sys.argv)
print(filecharcount(f))
```

#### As a fold

Character counting can be conveniently expressed in terms of fold/reduce. See the example below, which also generates column-wrapped output:

Works with: Python version 3
```'''Character counting as a fold'''

from functools import reduce
from itertools import repeat
from os.path import expanduser

# charCounts :: String -> Dict Char Int
def charCounts(s):
'''A dictionary of
(character, frequency) mappings
'''
def tally(dct, c):
dct[c] = 1 + dct[c] if c in dct else 1
return dct
return reduce(tally, list(s), {})

# TEST ----------------------------------------------------
# main :: IO ()
def main():
'''Listing in descending order of frequency.'''

print(
tabulated(
'Descending order of frequency:\n'
)(compose(repr)(fst))(compose(str)(snd))(
5
)(stet)(
sorted(
charCounts(
).items(),
key=swap,
reverse=True
)
)
)

# GENERIC -------------------------------------------------

# chunksOf :: Int -> [a] -> [[a]]
def chunksOf(n):
'''A series of lists of length n,
subdividing the contents of xs.
Where the length of xs is not evenly divible,
the final list will be shorter than n.'''
return lambda xs: reduce(
lambda a, i: a + [xs[i:n + i]],
range(0, len(xs), n), []
) if 0 < n else []

# compose (<<<) :: (b -> c) -> (a -> b) -> a -> c
def compose(g):
'''Right to left function composition.'''
return lambda f: lambda x: g(f(x))

# fst :: (a, b) -> a
def fst(tpl):
'''First member of a pair.'''
return tpl

# readFile :: FilePath -> IO String
'''The contents of any file at the path
derived by expanding any ~ in fp.'''
with open(expanduser(fp), 'r', encoding='utf-8') as f:

# paddedMatrix :: a -> [[a]] -> [[a]]
''''A list of rows padded to equal length
(where needed) with instances of the value v.'''
def go(rows):
len(max(rows, key=len))
)(v)(rows)
return lambda rows: go(rows) if rows else []

# paddedRows :: Int -> a -> [[a]] -[[a]]
'''A list of rows padded (but never truncated)
to length n with copies of value v.'''
def go(v, xs):
d = n - len(x)
return (x + list(repeat(v, d))) if 0 < d else x
return lambda v: lambda xs: go(v, xs) if xs else []

# showColumns :: Int -> [String] -> String
def showColumns(n):
'''A column-wrapped string
derived from a list of rows.'''
def go(xs):
def fit(col):
w = len(max(col, key=len))

return x.ljust(4 + w, ' ')

q, r = divmod(len(xs), n)
return '\n'.join(map(
fit,
chunksOf(q + int(bool(r)))(xs)
))
))
return lambda xs: go(xs)

# snd :: (a, b) -> b
def snd(tpl):
'''Second member of a pair.'''
return tpl

# stet :: a -> a
def stet(x):
'''The identity function.
The usual 'id' is reserved in Python.'''
return x

# swap :: (a, b) -> (b, a)
def swap(tpl):
'''The swapped components of a pair.'''
return (tpl, tpl)

# tabulated :: String -> (a -> String) ->
#                        (b -> String) ->
#                        Int ->
#                        (a -> b) -> [a] -> String
def tabulated(s):
'''Heading -> x display function -> fx display function ->
number of columns -> f -> value list -> tabular string.'''
def go(xShow, fxShow, intCols, f, xs):
def mxw(fshow, g):
return max(map(compose(len)(fshow), map(g, xs)))
w = mxw(xShow, lambda x: x)
fw = mxw(fxShow, f)
return s + '\n' + showColumns(intCols)([
xShow(x).rjust(w, ' ') + ' -> ' + (
fxShow(f(x)).rjust(fw, ' ')
)
for x in xs
])
return lambda xShow: lambda fxShow: lambda nCols: (
lambda f: lambda xs: go(
xShow, fxShow, nCols, f, xs
)
)

# MAIN ---
if __name__ == '__main__':
main()
```
Output:
```Descending order of frequency:

' ' -> 568     ')' ->  62     'v' ->  25     'w' ->   7     '5' ->   3
'\t' -> 382     '(' ->  62     '1' ->  24     'k' ->   7     '4' ->   3
'e' -> 274     'd' ->  60     'G' ->  22     '9' ->   6     '+' ->   3
'n' -> 233     'g' ->  59     ']' ->  17     'S' ->   5     '¬' ->   2
'\n' -> 228     'u' ->  58     '[' ->  17     'R' ->   5     '=' ->   2
't' -> 204     '|' ->  54     'λ' ->  16     'M' ->   5     '.' ->   2
's' -> 198     'x' ->  53     '2' ->  15     'F' ->   5     'L' ->   1
'-' -> 178     'm' ->  52     'N' ->  11     '<' ->   5     'C' ->   1
'i' -> 145     'c' ->  52     '}' ->  10     '6' ->   5     'A' ->   1
'o' -> 126     'h' ->  47     '{' ->  10     'z' ->   4     '3' ->   1
'f' -> 100     ':' ->  47     'T' ->  10     "'" ->   4     '&' ->   1
'r' ->  96     ',' ->  38     'I' ->  10     '^' ->   3     '\$' ->   1
'a' ->  86     'b' ->  32     '0' ->  10     'E' ->   3
'l' ->  70     'y' ->  31     '"' ->  10     '8' ->   3
'p' ->  68     '>' ->  28     'J' ->   9     '7' ->   3```

### Procedural

#### Without using collections.Counter

```import string
if hasattr(string, 'ascii_lowercase'):
letters = string.ascii_lowercase       # Python 2.2 and later
else:
letters = string.lowercase             # Earlier versions
offset = ord('a')

def countletters(file_handle):
"""Traverse a file and compute the number of occurences of each letter
return results as a simple 26 element list of integers."""
results =  * len(letters)
for line in file_handle:
for char in line:
char = char.lower()
if char in letters:
results[ord(char) - offset] += 1
# Ordinal minus ordinal of 'a' of any lowercase ASCII letter -> 0..25
return results

if __name__ == "__main__":
sourcedata = open(sys.argv)
lettercounts = countletters(sourcedata)
for i in xrange(len(lettercounts)):
print "%s=%d" % (chr(i + ord('a')), lettercounts[i]),
```

This example defines the function and provides a sample usage. The if ... __main__... line allows it to be cleanly imported into any other Python code while also allowing it to function as a standalone script. (A very common Python idiom).

Using a numerically indexed array (list) for this is artificial and clutters the code somewhat.

#### Using defaultdict

Works with: Python version 2.5+ and 3.x
```...
from collections import defaultdict
def countletters(file_handle):
"""Count occurences of letters and return a dictionary of them
"""
results = defaultdict(int)
for line in file_handle:
for char in line:
if char.lower() in letters:
c = char.lower()
results[c] += 1
return results
```

Which eliminates the ungainly fiddling with ordinal values and offsets in function countletters of a previous example above. More importantly it allows the results to be more simply printed using:

```lettercounts = countletters(sourcedata)
for letter,count in lettercounts.iteritems():
print "%s=%s" % (letter, count),
```

Again eliminating all fussing with the details of converting letters into list indices.

## Quackery

```  [ [] 26 times [ 0 join ] ]  is makecountnest (     --> [ )

[ char A char Z 1+ within ] is ischar        (   c --> b )

[ char A -
2dup peek 1+ unrot poke ] is tallychar     ( [ c --> [ )

[ makecountnest swap
witheach
[ upper dup ischar iff
tallychar
else drop ] ]         is countchars    (   \$ --> [ )

[ say "Letter count:" cr
witheach
[ say "  "
i^ char A + emit
say ":" echo
cr ] ]            is echocount     (   [ -->   )

[ sharefile 0 = if
join fail ]
countchars
echocount ]              is fileletters  (    \$ -->   )```

Testing in Quackery shell:

```O> \$ "quackery.py" fileletters ( i.e. the Quackery source file )
...
Letter count:
A:1324
B:433
C:819
D:897
E:2336
F:647
G:237
H:402
I:1393
J:82
K:359
L:683
M:537
N:1330
O:1171
P:835
Q:93
R:1393
S:1547
T:1769
U:697
V:105
W:257
X:281
Y:145
Z:34

Stack empty.

/O> \$ "nosuchfile.txt" fileletters
...

Quackery Stack:
Return stack: {[...] 0} {quackery 1} {[...] 11} {shell 5} {quackery 1} {[...] 1} {fileletters 4}```

## Quick Basic/QBASIC/PDS 7.1/VB-DOS

This version counts valid letters from A to Z (including Ñ in Spanish alphabet) or characters in a file. Takes in account accented vowels. It runs in QB, QBASIC, PDS 7.1 and VB_DOS as is.

```' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' '
'  Program CountCar                                   '
'                                                     '
'  This program counts how many distinct characters   '
'  have a text file specified by the user.            '
' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' '
' OPTION EXPLICIT  ' Remove comment in VB-DOS

' Register
TYPE regChar
Character AS STRING * 3
Count AS LONG
END TYPE

' Var
DIM iChar AS INTEGER
DIM iCL AS INTEGER
DIM iCountChars AS INTEGER
DIM iFile AS INTEGER
DIM i AS INTEGER
DIM lMUC AS LONG
DIM iMUI AS INTEGER
DIM lLUC AS LONG
DIM iLUI AS INTEGER
DIM iMaxIdx AS INTEGER
DIM iP AS INTEGER
DIM iPause AS INTEGER
DIM iPMI AS INTEGER
DIM iPrint AS INTEGER
DIM lHowMany AS LONG
DIM lTotChars AS LONG
DIM sTime AS SINGLE
DIM strFile AS STRING
DIM strTxt AS STRING
DIM strDate AS STRING
DIM strTime AS STRING
DIM strKey AS STRING
CONST LngReg = 256
CONST Letters = 1
CONST FALSE = 0
CONST TRUE = NOT FALSE

'------Main program cycle

' Initialize variables
strDate = DATE\$
strTime = TIME\$
iFile = FREEFILE

DO
CLS
PRINT "This program counts letters or characters in a text file."
PRINT
INPUT "File to open: ", strFile
OPEN strFile FOR BINARY AS #iFile
IF LOF(iFile) > 0 THEN
PRINT "Count: 1) Letters 2) Characters (1 or 2)";
DO
strKey = INKEY\$
LOOP UNTIL strKey = "1" OR strKey = "2"
PRINT ". Option selected: "; strKey
iCL = VAL(strKey)
sTime = TIMER
iP = POS(0)
lHowMany = LOF(iFile)
strTxt = SPACE\$(LngReg)

IF iCL = Letters THEN
iMaxIdx = 26
ELSE
iMaxIdx = 255
END IF

IF iMaxIdx <> iPMI THEN
iPMI = iMaxIdx
REDIM rChar(0 TO iMaxIdx) AS regChar

FOR i = 0 TO iMaxIdx
IF iCL = Letters THEN
strTxt = CHR\$(i + 65)
IF i = 26 THEN strTxt = CHR\$(165)
ELSE
SELECT CASE i
CASE 0: strTxt = "nul"
CASE 7: strTxt = "bel"
CASE 9: strTxt = "tab"
CASE 10: strTxt = "lf"
CASE 11: strTxt = "vt"
CASE 12: strTxt = "ff"
CASE 13: strTxt = "cr"
CASE 28: strTxt = "fs"
CASE 29: strTxt = "gs"
CASE 30: strTxt = "rs"
CASE 31: strTxt = "us"
CASE 32: strTxt = "sp"
CASE ELSE: strTxt = CHR\$(i)
END SELECT
END IF
rChar(i).Character = strTxt
NEXT i
ELSE
FOR i = 0 TO iMaxIdx
rChar(i).Count = 0
NEXT i
END IF

PRINT "Looking for ";
IF iCL = Letters THEN PRINT "letters.";  ELSE PRINT "characters.";
PRINT " File is"; STR\$(lHowMany); " in size. Working"; : COLOR 23: PRINT "..."; : COLOR (7)
DO WHILE LOC(iFile) < LOF(iFile)
IF LOC(iFile) + LngReg > LOF(iFile) THEN
strTxt = SPACE\$(LOF(iFile) - LOC(iFile))
END IF
GET #iFile, , strTxt
FOR i = 1 TO LEN(strTxt)
IF iCL = Letters THEN
iChar = ASC(UCASE\$(MID\$(strTxt, i, 1)))
SELECT CASE iChar
CASE 164: iChar = 165
CASE 160: iChar = 65
CASE 130, 144: iChar = 69
CASE 161: iChar = 73
CASE 162: iChar = 79
CASE 163, 129: iChar = 85
END SELECT
iChar = iChar - 65

' Validates if iChar is a letter
IF iChar >= 0 AND iChar <= 25 THEN
rChar(iChar).Count = rChar(iChar).Count + 1
ELSEIF iChar = 100 THEN ' CHR\$(165)
rChar(iMaxIdx).Count = rChar(iMaxIdx).Count + 1
END IF
ELSE
iChar = ASC(MID\$(strTxt, i, 1))
rChar(iChar).Count = rChar(iChar).Count + 1
END IF
NEXT i
LOOP
CLOSE #iFile

' Show the characters found
lMUC = 0
iMUI = 0
lLUC = 2147483647
iLUI = 0
iPrint = FALSE
lTotChars = 0
iCountChars = 0
iPause = FALSE
CLS
IF iCL = Letters THEN PRINT "Letters found: ";  ELSE PRINT "Characters found: ";
FOR i = 0 TO iMaxIdx
' Most Used Character
IF lMUC < rChar(i).Count THEN
lMUC = rChar(i).Count
iMUI = i
END IF

' Print character
IF rChar(i).Count > 0 THEN
strTxt = ""
IF iPrint THEN strTxt = ", " ELSE iPrint = TRUE
strTxt = strTxt + LTRIM\$(RTRIM\$(rChar(i).Character))
strTxt = strTxt + "=" + LTRIM\$(STR\$(rChar(i).Count))
iP = POS(0)
IF iP + LEN(strTxt) + 1 >= 80 AND iPrint THEN
PRINT ","
IF CSRLIN >= 23 AND NOT iPause THEN
iPause = TRUE
PRINT "Press a key to continue..."
DO
strKey = INKEY\$
LOOP UNTIL strKey <> ""
END IF
strTxt = MID\$(strTxt, 3)
END IF
PRINT strTxt;
lTotChars = lTotChars + rChar(i).Count
iCountChars = iCountChars + 1

' Least Used Character
IF lLUC > rChar(i).Count THEN
lLUC = rChar(i).Count
iLUI = i
END IF
END IF
NEXT i

PRINT "."

' Shows the summary
PRINT
PRINT "File analyzed....................: "; strFile
PRINT "Looked for.......................: "; : IF iCL = Letters THEN PRINT "Letters" ELSE PRINT "Characters"
PRINT "Total characters in file.........:"; lHowMany
PRINT "Total characters counted.........:"; lTotChars
IF iCL = Letters THEN PRINT "Characters discarded on count....:"; lHowMany - lTotChars
PRINT "Distinct characters found in file:"; iCountChars; "of"; iMaxIdx + 1
PRINT "Most used character was..........: ";
iPrint = FALSE
FOR i = 0 TO iMaxIdx
IF rChar(i).Count = lMUC THEN
IF iPrint THEN PRINT ", ";  ELSE iPrint = TRUE
PRINT RTRIM\$(LTRIM\$(rChar(i).Character));
END IF
NEXT i
PRINT " ("; LTRIM\$(STR\$(rChar(iMUI).Count)); " times)"
PRINT "Least used character was.........: ";
iPrint = FALSE
FOR i = 0 TO iMaxIdx
IF rChar(i).Count = lLUC THEN
IF iPrint THEN PRINT ", ";  ELSE iPrint = TRUE
PRINT RTRIM\$(LTRIM\$(rChar(i).Character));
END IF
NEXT i
PRINT " ("; LTRIM\$(STR\$(rChar(iLUI).Count)); " times)"
PRINT "Time spent in the process........:"; TIMER - sTime; "seconds"
ELSE
' File does not exist
CLOSE #iFile
KILL strFile
PRINT
PRINT "File does not exist."
END IF

' Again?
PRINT
PRINT "Again? (Y/n)"
DO
strTxt = UCASE\$(INKEY\$)
LOOP UNTIL strTxt = "N" OR strTxt = "Y" OR strTxt = CHR\$(13) OR strTxt = CHR\$(27)
LOOP UNTIL strTxt = "N" OR strTxt = CHR\$(27)

CLS
PRINT "End of execution."
PRINT "Start time: "; strDate; " "; strTime; ", end time: "; DATE\$; " "; TIME\$; "."
END
' ---End of main program cycle```

Output:

```This program counts letters or characters in a text file.

Count: 1) Letters 2) Characters (1 or 2). Option selected: 1
Looking for letters. File is 23769 in size. Working...

Letters found: A=1427, B=306, C=583, D=530, E=2098, F=279, G=183, H=501,
I=1177, J=15, K=34, L=741, M=379, N=1219, O=1183, P=312, Q=32, R=1105, S=1079,
T=1309, U=660, V=346, W=147, X=190, Y=242, Z=70, Ñ=5.

Looked for.......................: Letters
Total characters in file.........: 23769
Total characters counted.........: 16152
Distinct characters found in file: 27 of 27
Most used character was..........: E (2098 times)
Least used character was.........: Ñ (5 times)
Time spent in the process........: .3789063 seconds

Again? (Y/n)
```

## R

### Using summary

```letter.frequency <- function(filename)
{
file <- paste(readLines(filename), collapse = '')
chars <- strsplit(file, NULL)[]
summary(factor(chars))
}```

Usage on itself:

```> source('letter.frequency.r')
> letter.frequency('letter.frequency.r')
-  ,  .  '  (  )  [  ]  {  }  <  =  1  a  c  d  e  f  h  i  l  L  m  n  N  o  p  q  r  s  t  u  U  y
22  3  2  1  2  6  6  2  2  1  1  3  1  1  9  6  1 14  7  2  7  8  3  4  6  1  3  3  1  8  8  7  3  1  2```

### Using table

R's table function is more idiomatic. For variety, we will use read.delim rather than readLines and show how to only count letters. It is worth noting that readLines is prone to counting empty lines. This may be undesirable.

```letterFreq <- function(filename, lettersOnly)
{
txt <- read.delim(filename, header = FALSE, stringsAsFactors = FALSE, allowEscapes = FALSE, quote = "")
count <- table(strsplit(paste0(txt[,], collapse = ""), ""))
if(lettersOnly) count[names(count) %in% c(LETTERS, letters)] else count
}```
Output:

For fun, we'll use this page for input. However, HTML rarely parses well and the variety of text here is so large that I suspect inaccurate output.

```> print(letterFreq('https://rosettacode.org/wiki/Letter_frequency', TRUE))

a     A     b     B     c     C     d     D     e     E     f     F     g     G     h     H     i     I
38186   666  8008   350 16585  1263  4151   277 15020   713  3172   529  3079   149  4549   161  9397   690
j     J     k     K     l     L     m     M     n     N     o     O     p     P     q     Q     r     R
311   113  3294    76 15906   928  3333   322 26795   355  8926   456 22702   497  1877    39 15055   591
s     S     t     T     u     U     v     V     w     W     x     X     y     Y     z     Z
46527   695 15549   597  5268   269  1003   128  4134   148  1239   144  3037    55   127    77 ```

## Racket

```#lang racket
(require math)

(define (letter-frequencies ip)
(count-samples

(letter-frequencies (open-input-string "abaabdc"))
```
Output:
```'(#\a #\b #\d #\c)
'(3 2 1 1)
```

Using input from a text file:

```(letter-frequencies (open-input-file "somefile.txt"))
```

## Raku

(formerly Perl 6)

In Raku, whenever you want to count things in a collection, the rule of thumb is to use the Bag structure.

In response to some of the breathless exposition in the Frink entry.

• Has a Unicode-aware function, which intelligently enumerates through what a human would consider to be a single visible character. - Raku doesn't have a special Unicode aware string processing function, rather all of Rakus text/string wrangling functions are Unicode aware by default.
• Unicode-aware lowercase function. - See above: lowercase, uppercase, fold-case, title-case, all Unicode aware by default.
• Uses full Unicode tables to determine what is a "letter." - Um... Yeah, Unicode aware by default.
• Works with high Unicode characters, that is above \uFFFF. - OK, now we're just repeating ourselves.
• Normalize Unicode characters with its normalizeUnicode function. - Raku; normalized by default.
• Implements all of (NFC, NFD, NFKC, NFKD). NFC is the default. - Yep.

"How many other languages in this page do all or any of this correctly?" Quite a few I suspect. Some even moreso than Frink.

```.&ws.say for slurp.comb.Bag.sort: -*.value;

sub ws (\$pair) {
\$pair.key ~~ /\n/
?? ('NEW LINE' => \$pair.value)
!! \$pair.key ~~ /\s/
?? (\$pair.key.uniname => \$pair.value)
!! \$pair
}
```
Output when fed the same Les Misérables text file as used in the Word frequency task:
```SPACE => 522095
e => 325692
t => 222916
a => 199790
o => 180974
h => 170210
n => 167006
i => 165201
s => 157585
r => 145118
d => 106987
l => 97131
NEW LINE => 67662
u => 67340
c => 62717
m => 56021
f => 53494
w => 53301
, => 48784
g => 46060
p => 39932
y => 37985
b => 34276
. => 30589
v => 24045
" => 14340
k => 14169
T => 12547
- => 11037
I => 10067
A => 7355
H => 6600
M => 6206
; => 5885
E => 4968
C => 4583
S => 4392
' => 3938
x => 3692
! => 3539
R => 3531
P => 3424
O => 3401
j => 3390
B => 3185
W => 3180
N => 3053
? => 2976
F => 2754
G => 2508
: => 2468
J => 2448
L => 2444
q => 2398
V => 2200
_ => 2070
z => 1847
D => 1756
é => 1326
Y => 1238
U => 895
1 => 716
8 => 412
X => 333
K => 321
è => 292
3 => 259
2 => 248
5 => 220
0 => 218
* => 181
4 => 181
) => 173
( => 173
6 => 167
É => 146
7 => 143
Q => 135
] => 122
[ => 122
9 => 117
æ => 106
= => 75
ê => 74
Z => 59
à => 59
â => 56
> => 50
< => 50
/ => 50
ç => 48
NO-BREAK SPACE => 45
î => 39
ü => 37
| => 36
ô => 34
# => 26
ù => 18
ï => 18
Æ => 10
û => 9
+ => 5
È => 5
ë => 5
À => 4
@ => 2
ñ => 2
Ç => 2
\$ => 2
% => 1
& => 1
{ => 1
} => 1
½ => 1
```

## Raven

```define count_letters use \$words
{ } as \$wordHash    [ ] as \$keys   [ ]  as \$vals
\$words each chr
dup \$wordHash swap get 0 prefer 1 +   # stack: chr cnt
swap \$wordHash swap set
\$wordHash keys copy sort each
dup \$keys push
\$wordHash swap get \$vals push
\$keys \$vals combine  print "\n" print

"test.dat" as \$file
\$all_data count_letters```

## REXX

### version 1

It should be noted that the file being read is read one line at time, so the line-end characters (presumably the
line-feed, carriage return, new-line, or whatever control characters are being used) are not reported.

These characters could be read and reported if the   charin   BIF would be used instead of the   linein   BIF.

Also note that this REXX program is ASCII or EBCDIC independent, but what constitutes a letter is restricted to
the Latin (Roman) alphabet (that is, which characters are considered to be letters of a particular language.

The version of REXX that was used was the English version of Regina REXX.   It should be noted that almost all
REXX interpreters assume the English language for such things as determining what characters are considered
letters unless another language is specified   (Regina REXX uses an environmental variable for this purpose).

All characters are still counted, whether a letter or not, including non-displayable characters.

```/*REXX program counts the occurrences of all characters in a file,  and note that all   */
/* Latin alphabet letters are uppercased for also counting {Latin} letters (both cases).*/
/*════════════════════════════════════~~~~~~~~~~════════════════════════════════════════*/
abc = 'abcdefghijklmnopqrstuvwxyz'               /*define an (Latin or English) alphabet*/
abcU= 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'               /*define an uppercase version of  [↑]. */
parse arg fileID .                               /*this last char isn't a middle dot: · */
if fileID==''  then fileID= 'JUNK.TXT'           /*¿none specified? Then use the default*/
totChars= 0;           totLetters= 0             /*count of all chars and of all letters*/
pad= left('',18);      pad9= left('', 18%2)      /*used for the indentations of output. */
@.= 0                                            /*wouldn't it be neat to use Θ instead?*/
do j=1  while lines(fileID)\==0             /*read the file 'til the cows come home*/
rec= linein(fileID)                         /*get a line/record from the input file*/
/* [↓]  process all characters in  REC.*/
do k=1  for length(rec)                   /*examine/count each of the characters.*/
totChars= totChars + 1                    /*bump count of number of characters.  */
c= substr(rec, k, 1);      @.c= @.c + 1   /*Peel off a character; bump its count.*/
if \datatype(c, 'M')  then iterate        /*Not a Latin letter?   Get next char.⌠*/
totLetters= totLetters + 1                /*bump the count for [Latin] letters. ⌡*/
upper c                                   /* ◄─────◄ uppercase a Latin character.*/
@..c= @..c + 1                            /*bump the  (Latin)  letter's count.   */
end   /*k*/                               /*no Greek glyphs:  αßΓπΣσµτΦΘΩδφε ··· */
end     /*j*/                               /*maybe we're ½ done by now, or mäÿbé ¬*/
LL= '(Latin) letter'   /*literal used for a  "SAY"  (below).  */
w= length(totChars)                              /*used for right─aligning the counts.  */
say 'file ─────'  fileId  "───── has"   j-1   'records and has'   totLetters LL"s.";   say
do L=0  for 256;    c= d2c(L)               /*display all none─zero letter counts. */
if @..c==0  then iterate                    /*Has a zero count? Then skip character*/
say pad9  LL' '    c    " (also" translate(c,abc,abcU)')  count:'      right(@..c, w)
end   /*L*/                                 /*we may be in a rut, but not a cañyon.*/
say                                              /*¡The old name for Eygpt was Æygpt!  _*/
say 'file ─────'    fileId     "───── has"     totChars     'characters.'          /* √ */
say                                              /*The name for « » chars is guillemets.*/
do #=0  for 256;    y= d2c(#)               /*display all none─zero char counts.   */
if @.y==0  then iterate                     /*¿Å zero count?  Then ignore character*/
c= d2c(#);               ch= c              /*C  is the character glyph of a char. */
if c<<' ' | #==255  then ch=                /*don't show some control characters.  */
if c==' '           then ch= 'blank'        /*show a blank's  {true}  name.        */
say pad right(ch, 5)         " ('"d2x(#,2)"'x  character count:"      right(@.c, w)
end   /*#*/                                 /*255 isn't quite ∞, but sometimes ∙∙∙ */
say                                              /*not a good place for dithering: ░▒▓█ */
say  pad   pad9   '☼ end─of─list ☼'              /*show we are at the end of the list.  */
/*§§§§ Talk about a mishmash of 2¢ comments. ▬▬^▬▬ stick a fork in it, we're all done. ☻*/
```

output   when using the (above) REXX program for the input file:

Note that this REXX program works with ASCII or EBCDIC, but the order of the output will
be different because of the order in which EBCDIC and ASCII stores characters.

```file ───── JUNK.TXT ───── has 42 records and has 1652 (Latin) letters.

(Latin) letter  A  (also a)  count:  146
(Latin) letter  B  (also b)  count:   26
(Latin) letter  C  (also c)  count:  104
(Latin) letter  D  (also d)  count:   58
(Latin) letter  E  (also e)  count:  187
(Latin) letter  F  (also f)  count:   53
(Latin) letter  G  (also g)  count:   25
(Latin) letter  H  (also h)  count:   80
(Latin) letter  I  (also i)  count:   89
(Latin) letter  J  (also j)  count:    6
(Latin) letter  K  (also k)  count:   13
(Latin) letter  L  (also l)  count:   97
(Latin) letter  M  (also m)  count:   28
(Latin) letter  N  (also n)  count:  102
(Latin) letter  O  (also o)  count:  106
(Latin) letter  P  (also p)  count:   38
(Latin) letter  Q  (also q)  count:    3
(Latin) letter  R  (also r)  count:  111
(Latin) letter  S  (also s)  count:   96
(Latin) letter  T  (also t)  count:  175
(Latin) letter  U  (also u)  count:   48
(Latin) letter  V  (also v)  count:    3
(Latin) letter  W  (also w)  count:   18
(Latin) letter  X  (also x)  count:    9
(Latin) letter  Y  (also y)  count:   25
(Latin) letter  Z  (also z)  count:    6

file ───── JUNK.TXT ───── has 3778 characters.

('02'x  character count:    1
('0F'x  character count:    2
('11'x  character count:    2
('15'x  character count:    4
('16'x  character count:    4
('18'x  character count:    1
('19'x  character count:    1
blank  ('20'x  character count: 1477
!  ('21'x  character count:    1
"  ('22'x  character count:   14
#  ('23'x  character count:    6
%  ('25'x  character count:    1
'  ('27'x  character count:   47
(  ('28'x  character count:   23
)  ('29'x  character count:   22
*  ('2A'x  character count:   86
+  ('2B'x  character count:    4
,  ('2C'x  character count:   16
-  ('2D'x  character count:    1
.  ('2E'x  character count:   40
/  ('2F'x  character count:   88
0  ('30'x  character count:    8
1  ('31'x  character count:   10
2  ('32'x  character count:   11
5  ('35'x  character count:    7
6  ('36'x  character count:    2
8  ('38'x  character count:    2
9  ('39'x  character count:    3
:  ('3A'x  character count:    5
;  ('3B'x  character count:    8
<  ('3C'x  character count:    2
=  ('3D'x  character count:   38
?  ('3F'x  character count:    5
@  ('40'x  character count:    9
A  ('41'x  character count:    2
B  ('42'x  character count:    1
C  ('43'x  character count:    8
D  ('44'x  character count:    6
E  ('45'x  character count:    5
F  ('46'x  character count:    1
G  ('47'x  character count:    3
H  ('48'x  character count:    2
I  ('49'x  character count:    8
J  ('4A'x  character count:    2
K  ('4B'x  character count:    2
L  ('4C'x  character count:   22
M  ('4D'x  character count:    2
N  ('4E'x  character count:    3
O  ('4F'x  character count:    1
P  ('50'x  character count:    2
Q  ('51'x  character count:    1
R  ('52'x  character count:    3
S  ('53'x  character count:    2
T  ('54'x  character count:    9
U  ('55'x  character count:    4
V  ('56'x  character count:    1
W  ('57'x  character count:    1
X  ('58'x  character count:    4
Y  ('59'x  character count:    2
Z  ('5A'x  character count:    1
[  ('5B'x  character count:    3
\  ('5C'x  character count:    2
]  ('5D'x  character count:    3
^  ('5E'x  character count:    1
_  ('5F'x  character count:    1
a  ('61'x  character count:  144
b  ('62'x  character count:   25
c  ('63'x  character count:   96
d  ('64'x  character count:   52
e  ('65'x  character count:  182
f  ('66'x  character count:   52
g  ('67'x  character count:   22
h  ('68'x  character count:   78
i  ('69'x  character count:   81
j  ('6A'x  character count:    4
k  ('6B'x  character count:   11
l  ('6C'x  character count:   75
m  ('6D'x  character count:   26
n  ('6E'x  character count:   99
o  ('6F'x  character count:  105
p  ('70'x  character count:   36
q  ('71'x  character count:    2
r  ('72'x  character count:  108
s  ('73'x  character count:   94
t  ('74'x  character count:  166
u  ('75'x  character count:   44
v  ('76'x  character count:    2
w  ('77'x  character count:   17
x  ('78'x  character count:    5
y  ('79'x  character count:   23
z  ('7A'x  character count:    5
{  ('7B'x  character count:    2
|  ('7C'x  character count:    1
}  ('7D'x  character count:    2
~  ('7E'x  character count:   10
é  ('82'x  character count:    1
ä  ('84'x  character count:    1
Å  ('8F'x  character count:    1
Æ  ('92'x  character count:    1
ÿ  ('98'x  character count:    1
¢  ('9B'x  character count:    1
ñ  ('A4'x  character count:    1
¿  ('A8'x  character count:    2
¬  ('AA'x  character count:    1
½  ('AB'x  character count:    1
«  ('AE'x  character count:    1
»  ('AF'x  character count:    1
░  ('B0'x  character count:    1
▒  ('B1'x  character count:    1
▓  ('B2'x  character count:    1
─  ('C4'x  character count:   30
═  ('CD'x  character count:   76
█  ('DB'x  character count:    1
α  ('E0'x  character count:    1
ß  ('E1'x  character count:    1
Γ  ('E2'x  character count:    1
π  ('E3'x  character count:    1
Σ  ('E4'x  character count:    1
σ  ('E5'x  character count:    1
µ  ('E6'x  character count:    1
τ  ('E7'x  character count:    1
Φ  ('E8'x  character count:    1
Θ  ('E9'x  character count:    2
Ω  ('EA'x  character count:    1
δ  ('EB'x  character count:    1
∞  ('EC'x  character count:    1
φ  ('ED'x  character count:    1
ε  ('EE'x  character count:    1
⌠  ('F4'x  character count:    1
⌡  ('F5'x  character count:    1
∙  ('F9'x  character count:    3
·  ('FA'x  character count:    4
√  ('FB'x  character count:    1

☼ end─of─list ☼
```

### Version 2 (for TSO)

```/*REXX program counts the occurences of all characters in a file
* No translation to uppercase takes place
* There is no need for tails being hex
* 25.07.2012 Walter Pachl
***********************************************************************/

Parse arg dsn .                    /*Data set to be processed       */
if dsn='' Then                     /*none specified?                */
dsn='PRIV.V100(TEST)'            /* Use default.                  */
c.=0                               /* Character counts              */
"ALLOC   FI(IN) DA("dsn") SHR REUSE"
'EXECIO   * DISKR IN (STEM L. FINIS'
'FREE   FI(IN)'
totChars=0                         /*count of the total num of chars*/
totLetters=0                       /*count of the total num letters.*/
indent=left('',20)                 /*used for indentation of output.*/

do j=1 to l.0                      /*process all lines              */
rec=l.j                          /*take line number j             */
Say '>'rec'<' length(rec)        /*that's in PRIV.V100(TEST)      */
Say ' E8C44D8FF015674BCDEF'
Say ' 61100711200000000002'
do k=1 for length(rec)           /*loop over characters           */
totChars=totChars+1            /*Increment total number of chars*/
c=substr(rec,k,1)              /*get character number k         */
c.c=c.c+1                      /*increment the character's count*/
End
End                              /*maybe we're ½ done by now, or ¬*/

w=length(totChars)                 /*used for right-aligning counts.*/
say 'file -----' dsn "----- has" j-1 'records.'
say 'file -----' dsn "----- has" totChars 'characters.'

do L=0 to 255                      /* display nonzero letter counts */
c=d2c(l)                         /* the character in question     */
if c.c>0 &,                      /* was found in the file         */
datatype(c,'M')>0 Then Do     /* and is a Latin letter         */
say indent "(Latin) letter " c 'count:' right(c.c,w) /* tell    */
totLetters=totLetters+c.c      /* increment number of letters   */
End
End

say 'file -----' dsn "----- has" totLetters '(Latin) letters.'
say '                           other characters follow'
other=0
do m=0 to 255                      /* now for non-letters           */
c=d2c(m)                         /* the character in question     */
y=c2x(c)                         /* the hex representation        */
if c.c>0 &,                      /* was found in the file         */
datatype(c,'M')=0 Then Do     /* and is not a Latin letter     */
other=other+c.c                /* increment count               */
_=right(c.c,w)                 /* prepare output of count       */
select                         /*make the character viewable.   */
when c<<' ' | m==255 then say indent  "'"y"'x character count:" _
when c==' '          then say indent   "blank character count:" _
otherwise                 say indent "   " c 'character count:' _
end
end
end
say 'file -----' dsn "----- has" other 'other characters.'
```

Output:

```>WaA  Pa12 :&-: :äüÖ2< 20
E8C44D8FF015674BCDEF
61100711200000000002
file ----- PRIV.V100(TEST) ----- has 1 records.
file ----- PRIV.V100(TEST) ----- has 20 characters.
(Latin) letter  a count:  2
(Latin) letter  A count:  1
(Latin) letter  P count:  1
(Latin) letter  W count:  1
file ----- PRIV.V100(TEST) ----- has 5 (Latin) letters.
'00'x character count:  1
'10'x character count:  1
blank character count:  3
& character count:  1
- character count:  1
: character count:  1
: character count:  1
ä character count:  1
ü character count:  1
Ö character count:  1
1 character count:  1
2 character count:  2
file ----- PRIV.V100(TEST) ----- has 15 other characters.```

## Ring

```textData = read("C:\Ring\ReadMe.txt")
ln =len(textData)
charCount = list(255)
totCount = 0

for i =1 to ln
char = ascii(substr(textData,i,1))
charCount[char] = charCount[char] + 1
if char > 31 totCount = totCount + 1 ok
next

for i = 32 to 255
if charCount[i] > 0 see char(i) + " = " + charCount[i] + " " + (charCount[i]/totCount)*100 + " %" + nl ok
next```

## Ruby

```def letter_frequency(file)
letters = 'a' .. 'z'
split(//) .
group_by {|letter| letter.downcase} .
select   {|key, val| letters.include? key} .
collect  {|key, val| [key, val.length]}
end

letter_frequency(ARGV).sort_by {|key, val| -val}.each {|pair| p pair}
```

example output, using the program file as input:

```\$ ruby letterFrequency.rb letterFrequency.rb
["e", 34]
["l", 20]
["t", 17]
["r", 14]
["a", 12]
["y", 9]
["c", 8]
["i", 7]
["v", 6]
["n", 6]
["f", 6]
["s", 6]
["d", 5]
["p", 5]
["k", 5]
["u", 4]
["o", 4]
["g", 3]
["b", 2]
["h", 2]
["q", 2]
["z", 1]
["w", 1]```

### Ruby 2.0

```def letter_frequency(file)
freq = Hash.new(0)
file.each_char.lazy.grep(/[[:alpha:]]/).map(&:upcase).each_with_object(freq) do |char, freq_map|
freq_map[char] += 1
end
end

letter_frequency(ARGF).sort.each do |letter, frequency|
puts "#{letter}: #{frequency}"
end
```

note that this version *should* use less memory, even on a gigantic file. This is done by using lazy enumerables, which ruby 2.0 introduces.

example output, using the (somewhat large) dictionary file as the input. Also note that this versions works on unicode text.

```\$ ruby letter_frequency.rb /usr/share/dict/words
A: 64439
B: 15526
C: 31872
D: 28531
E: 88833
F: 10675
G: 22712
H: 19320
I: 66986
J: 1948
K: 8409
L: 41107
M: 22508
N: 57144
O: 48944
P: 22274
Q: 1524
R: 57347
S: 90113
T: 53006
U: 26118
V: 7989
W: 7530
X: 2124
Y: 12652
Z: 3281
Å: 1
á: 10
â: 6
ä: 7
å: 3
ç: 5
è: 28
é: 144
ê: 6
í: 2
ñ: 8
ó: 8
ô: 2
ö: 16
û: 3
ü: 12
```

### Ruby 2.7

Ruby 2.7 introduced "tally", which delivers a tally on anything enumerable.

```p File.open("/usr/share/dict/words","r").each_char.tally
```

## Run BASIC

```open "c:\rbp101\public\textFile.txt" for input as #f
textData\$ = input\$(#f, lof( #f))
ln =len(textData\$)
close #f

dim charCount( 255)

for i =1 to ln
char            = asc(mid\$(textData\$,i,1))
charCount(char) = charCount(char) + 1
if char > 31 then totCount = totCount + 1
next i

for i = 32 to 255
if charCount(i) > 0 then print "Ascii:";using("###",i);" char:";chr\$(i);" Count:";using("#######",charCount(i));" ";using("##.#",(charCount(i) / totCount) * 100);"%"
next i```

Output uses this program to count itself:

```Ascii: 32 char:  Count:     76 16.1%
Ascii: 34 char:" Count:     18  3.8%
Ascii: 35 char:# Count:     17  3.6%
Ascii: 36 char:\$ Count:      6  1.3%
Ascii: 37 char:% Count:      1  0.2%
Ascii: 40 char:( Count:     16  3.4%
Ascii: 41 char:) Count:     16  3.4%
Ascii: 42 char:* Count:      1  0.2%
Ascii: 43 char:+ Count:      2  0.4%
Ascii: 44 char:, Count:      6  1.3%
Ascii: 46 char:. Count:      2  0.4%
Ascii: 47 char:/ Count:      1  0.2%
Ascii: 48 char:0 Count:      4  0.8%
Ascii: 49 char:1 Count:      8  1.7%
Ascii: 50 char:2 Count:      3  0.6%
Ascii: 51 char:3 Count:      2  0.4%
Ascii: 53 char:5 Count:      4  0.8%
Ascii: 58 char:: Count:      4  0.8%
Ascii: 59 char:; Count:      8  1.7%
Ascii: 61 char:= Count:      7  1.5%
Ascii: 62 char:> Count:      2  0.4%
Ascii: 65 char:A Count:      1  0.2%
Ascii: 67 char:C Count:     10  2.1%
Ascii: 68 char:D Count:      3  0.6%
Ascii: 70 char:F Count:      1  0.2%
Ascii: 92 char:\ Count:      3  0.6%
Ascii: 97 char:a Count:     19  4.0%
Ascii: 98 char:b Count:      2  0.4%
Ascii: 99 char:c Count:     17  3.6%
Ascii:100 char:d Count:      3  0.6%
Ascii:101 char:e Count:     13  2.7%
Ascii:102 char:f Count:     10  2.1%
Ascii:103 char:g Count:      3  0.6%
Ascii:104 char:h Count:     14  3.0%
Ascii:105 char:i Count:     24  5.1%
Ascii:108 char:l Count:      7  1.5%
Ascii:109 char:m Count:      2  0.4%
Ascii:110 char:n Count:     25  5.3%
Ascii:111 char:o Count:     21  4.4%
Ascii:112 char:p Count:      6  1.3%
Ascii:114 char:r Count:     17  3.6%
Ascii:115 char:s Count:      7  1.5%
Ascii:116 char:t Count:     38  8.0%
Ascii:117 char:u Count:     16  3.4%
Ascii:120 char:x Count:      7  1.5%
```

## Rust

Works with all UTF-8 characters

```use std::collections::btree_map::BTreeMap;
use std::{env, process};
use std::fmt::Display;
use std::fs::File;

fn main() {
let filename = env::args().nth(1)
.unwrap_or_else(|e| exit_err(e, 1));

let mut buf = String::new();
let mut count = BTreeMap::new();

File::open(&filename)
.unwrap_or_else(|e| exit_err(e, 2))
.unwrap_or_else(|e| exit_err(e, 3));

for c in buf.chars() {
*count.entry(c).or_insert(0) += 1;
}

println!("Number of occurences per character");
for (ch, count) in &count {
println!("{:?}: {}", ch, count);
}
}

#[inline]
fn exit_err<T>(msg: T, code: i32) -> ! where T: Display {
writeln!(&mut io::stderr(), "{}", msg).expect("Could not write to stderr");
process::exit(code)
}
```

Output when run on source file:

```Number of occurences per character
'\n': 35
' ': 167
'!': 4
'\"': 10
'#': 1
'&': 4
'(': 25
')': 25
'*': 1
'+': 1
',': 12
'-': 1
'.': 10
'0': 1
'1': 3
'2': 2
'3': 2
':': 37
';': 13
'<': 1
'=': 4
'>': 2
'?': 1
'B': 2
'C': 1
'D': 2
'F': 2
'M': 2
'N': 1
'P': 1
'R': 1
'S': 1
'T': 5
'W': 1
'[': 1
']': 1
'_': 15
'a': 20
'b': 5
'c': 22
'd': 12
'e': 75
'f': 14
'g': 5
'h': 6
'i': 29
'k': 1
'l': 23
'm': 13
'n': 36
'o': 28
'p': 17
'r': 45
's': 33
't': 42
'u': 24
'v': 2
'w': 8
'x': 6
'y': 4
'{': 9
'|': 6
'}': 9
```

## S-BASIC

Because S-BASIC lacks an EOF function, some extra care is required to avoid reading beyond the end of file. (CP/M text files are normally terminated with a Ctrl-Z byte, but not all text editors enforce this convention if the file would otherwise end on a sector boundary.)

```\$constant EOF = 1AH       rem  normal end-of-file marker

rem  Convert character to upper case
function upcase(ch = char) = char
if ch >= 'a' and ch <= 'z' then
ch = ch - 32
end = ch

rem  Convert string to all upper case characters
function allcaps(source = string) = string
var p = integer
for p = 1 to len(source) do
mid(source,p,1) = upcase(mid(source,p,1))
next p
end = source

comment
Preserve console and printer channels (#0 and #1)
Channel #2 declared as sequential ASCII
end
files d, d, sa(1)

var ch = char
var i = integer
based errcode = integer
base errcode at 103H       rem  S-BASIC stores run-time error code here
var filename = string
var total = real
dim real freq(26)

input "Name of text file to process: "; filename
filename = allcaps(filename)
open #2; filename
on error goto 7_trap    rem  In case input file lacks terminating ^Z

rem  Initialize letter counts to zero
for i = 1 to 26
freq(i) = 0
next i

rem  Process the file
total = 0
input3 #2; ch
while ch <> EOF do
begin
ch = upcase(ch);
if ch >= "A" and ch <= "Z" then
begin
freq(ch - 64) = freq(ch - 64) + 1
total = total + 1
end
input3 #2; ch
end

goto 8_done      rem  Jump around error trap

7_trap	if errcode <> 15 then
begin
print "Runtime error = ";errcode
goto 9_exit
end
rem  otherwise fall through on attempted read past EOF (err = 15)
8_done
close #2

rem  Report results
print "Letter   Count   Percent"
for I = 1 to 26
print chr(i+64);"      ";
print using " ##,###"; freq(i);
print using "    ##.#"; freq(i) / total * 100
next i

9_exit
end```
Output:

With Lincoln's Second Inaugural Address used as input

```Letter  Count   Percent
A         101       8.8
B          14       1.2
C          31       2.7
D          59       5.1
E         165      14.3
F          27       2.3
G          28       2.4
H          80       7.0
I          68       5.9
J           0       0.0
K           3       0.3
L          42       3.7
M          13       1.1
N          78       6.8
O          93       8.1
P          15       1.3
Q           1       0.1
R          79       6.9
S          44       3.8
T         126      11.0
U          21       1.8
V          23       2.0
W          28       2.4
X           0       0.0
Y          11       1.0
Z           0       0.0
```

## Scala

```import io.Source.fromFile

def letterFrequencies(filename: String) =
fromFile(filename).mkString groupBy (c => c) mapValues (_.length)
```

## Scheme

Using guile scheme 2.0.11.

Note that this prints the scheme representations of characters in no particular order.

```(use-modules (ice-9 format))

(define (char-freq port table)
(if
(eof-object? (peek-char port))
table

(cond
((null? table) (list (list char 1)))
((eq? (caar table) char) (cons (list char (+ (cadar table) 1)) (cdr table)))
(#t (cons (car table) (add-char char (cdr table))))))

(define (format-table table)
(for-each (lambda (t) (format #t "~10s~10d~%" (car t) (cadr t))) table))

(define (print-freq filename)
(format-table (char-freq (open-input-file filename) '())))

(print-freq "letter-frequency.scm")
```

```#\(               45
#\u                5
#\s                9
#\e               47
#\-               19
#\m                9
#\o               16
#\d               19
#\l               25
#\space           83
#\i               15
#\c               28
#\9                1
#\f               20
#\r               39
#\a               47
#\t               36
#\)               45
#\newline         21
#\n               15
#\h               14
#\q                7
#\p                9
#\b               16
#\j                1
#\?                3
#\k                1
#\1                4
#\+                1
#\#                2
#\"                4
#\~                3
#\0                2
#\%                1
#\'                1
#\y                1
#\.                1
```

An implementation for CHICKEN scheme:

```(with-input-from-string "foobar"
(lambda ()
(port-fold (lambda (x s)
(alist-update x
(add1 (alist-ref x s eq? 0))
s))
'()
```

which shows: ((#\f . 1) (#\o . 2) (#\b . 1) (#\a . 1) (#\r . 1))

## Seed7

```\$ include "seed7_05.s7i";

const type: charHash is hash [char] integer;

const proc: main is func
local
var charHash: numberOfChars is charHash.EMPTY_HASH;
var char: ch is ' ';
begin
ch := getc(IN);
while ch <> EOF do
if ch in numberOfChars then
incr(numberOfChars[ch]);
else
numberOfChars @:= [ch] 1;
end if;
ch := getc(IN);
end while;
for ch range sort(keys(numberOfChars)) do
writeln(ch <& " " <& numberOfChars[ch]);
end for;
end func;```

Output when the program uses itself as input:

``` 22
129
" 4
\$ 1
& 2
' 2
( 6
) 6
. 2
0 1
...
s 21
t 9
u 9
v 2
w 3
y 2```

## SenseTalk

```put file "~/Documents/addresses.csv" into source

repeat with each character of source
if it is a controlChar then next repeat -- skip control characters
if it is a lowercase then put "." after it -- make keys distinct
end repeat

repeat with each (theChar, count) in counts
put char 1 of theChar & " —> " & count
end repeat```

Output:

```  —> 2862
" —> 11180
# —> 109
& —> 58
, —> 5646
- —> 2009
. —> 1629
/ —> 1000
0 —> 1496
1 —> 1665
2 —> 1487
3 —> 1481
4 —> 1405
5 —> 1416
6 —> 1260
7 —> 1499
8 —> 1323
9 —> 1349
: —> 500
@ —> 500
_ —> 127
A —> 558
a —> 4082
B —> 290
b —> 455
C —> 572
c —> 2387
D —> 273
d —> 1230
E —> 265
e —> 4493
F —> 177
f —> 392
G —> 146
g —> 911
H —> 239
h —> 1699
I —> 235
i —> 2935
J —> 212
j —> 147
K —> 131
k —> 646
L —> 302
l —> 2602
M —> 428
m —> 1912
N —> 319
n —> 3237
O —> 136
o —> 4018
P —> 294
p —> 1141
Q —> 6
q —> 228
R —> 288
r —> 3124
S —> 600
s —> 2229
T —> 196
t —> 3328
U —> 21
u —> 899
V —> 65
v —> 508
W —> 222
w —> 1937
X —> 34
x —> 153
Y —> 99
y —> 858
Z —> 14
z —> 145
```

## Sidef

```func letter_frequency(File file) {
.group_by {|letter| letter.downcase}    \
.map_val  {|_, val| val.len}            \
.sort_by  {|_, val| -val}
}

var top = letter_frequency(File(__FILE__))
top.each{|pair| say "#{pair}: #{pair}"}
```
Output:
```e: 22
l: 17
a: 16
t: 14
r: 14
p: 12
f: 8
i: 8
n: 7
c: 6
u: 6
o: 6
v: 6
y: 5
s: 5
h: 3
w: 2
q: 2
b: 2
m: 2
g: 2
d: 1
```

## SIMPOL

Example: open a text file and compute letter frequency.

```constant iBUFSIZE 500

function main(string filename)
fsfileinputstream fpi
integer e, i, aval, zval, cval
string s, buf, c
array chars

e = 0
fpi =@ fsfileinputstream.new(filename, error=e)
if fpi =@= .nul
else
chars =@ array.new()
aval = .charval("a")
zval = .charval("z")
i = 1
while i <= 26
chars[i] = 0
i = i + 1
end while
buf = .lcase(fpi.getstring(iBUFSIZE, 1))
while not fpi.endofdata and buf > ""
i = 1
while i <= .len(buf)
c = .substr(buf, i, 1)
cval = .charval(c)
if cval >= aval and cval <= zval
chars[cval - aval + 1] = chars[cval - aval + 1] + 1
end if
i = i + 1
end while
buf = .lcase(fpi.getstring(iBUFSIZE, 1))
end while

s = "Character counts for """ + filename + """{d}{a}"
i = 1
while i <= chars.count()
s = s + .char(aval + i - 1) + ": " + .tostr(chars[i], 10) + "{d}{a}"
i = i + 1
end while
end if
end function s```

As this was being created I realized that in [SIMPOL] I wouldn't have done it this way (in fact, I wrote it differently the first time and had to go back and change it to use an array afterward). In [SIMPOL] we would have used the set object. It acts similarly to a single-dimensional array, but can also use various set operations, such as difference, unite, intersect, etc. One of th einteresting things is that each unique value is stored only once, and the number of duplicates is stored with it. The sample then looks a little cleaner:

```constant iBUFSIZE 500

function main(string filename)
fsfileinputstream fpi
integer e, i, aval, zval
string s, buf, c
set chars

e = 0
fpi =@ fsfileinputstream.new(filename, error=e)
if fpi =@= .nul
else
chars =@ set.new()
aval = .charval("a")
zval = .charval("z")
buf = .lcase(fpi.getstring(iBUFSIZE, 1))
while not fpi.endofdata and buf > ""
i = 1
while i <= .len(buf)
c = .substr(buf, i, 1)
if .charval(c) >= aval and .charval(c) <= zval
end if
i = i + 1
end while
buf = .lcase(fpi.getstring(iBUFSIZE, 1))
end while

s = "Character counts for """ + filename + """{d}{a}"
i = 1
while i <= chars.count()
s = s + chars[i] + ": " + .tostr(chars.valuecount(chars[i]), 10) + "{d}{a}"
i = i + 1
end while
end if
end function s```

The final stage simply reads the totals for each character. One caveat, if a character is unrepresented, then it will not show up at all in this second implementation.

## Smalltalk

Make it a bag of characters and get the counts:

Works with: Smalltalk/X
```bagOfChars := 'someFile' asFilename contentsAsString asBag.
bag sortedCounts
select:[:assoc | assoc value isLetter ]
thenDo:[:assoc | assoc printCR].
```

If the file is huge, you may not want to read it in as a big string first, but feed the chars linewise into the bag:

```bagOfChars := Bag new.
bag sortedCounts ...
```

To show all counts (as opposed to selecting the letter counts only), replace the "select:thenDo:" by a simple "do:", as in:

```bag sortedCounts do:[:assoc | assoc printCR].
```

or even shorter:

```bag sortedCounts do:#printCR.
```
Output:
```27->e
20->n
16->o
16->u
16->d
...```

If you prefer seeing the character first, followed by the count, replace the do-loop's action with:

```... do:[:assoc | '%s -> %s\n' printf:{assoc value . assoc key} on:Stdout ].
```
Output:
```e -> 27
n -> 20
u -> 16
d -> 16
...```

## Swift

```import Foundation

let dictPath: String

switch CommandLine.arguments.count {
case 2:
dictPath = CommandLine.arguments
case _:
dictPath = "/usr/share/dict/words"
}

let wordsData = FileManager.default.contents(atPath: dictPath)!
let allWords = String(data: wordsData, encoding: .utf8)!
let words = allWords.components(separatedBy: "\n")
let counts = words.flatMap({ \$0.map({ (\$0, 1) }) }).reduce(into: [:], { \$0[\$1.0, default: 0] += \$1.1 })

for (char, count) in counts {
print("\(char): \(count)")
}
```

## Tcl

```proc letterHistogram {fileName} {
# Initialize table (in case of short texts without every letter)
for {set i 97} {\$i<=122} {incr i} {
set frequency([format %c \$i]) 0
}
# Iterate over characters in file
set f [open \$fileName]
foreach c [split [read \$f] ""] {
# Count them if they're alphabetic
if {[string is alpha \$c]} {
incr frequency([string tolower \$c])
}
}
close \$f
# Print the histogram
parray frequency
}

letterHistogram the/sample.txt
```

## TUSCRIPT

```\$\$ MODE TUSCRIPT
words = REQUEST ("http://www.puzzlers.org/pub/wordlists/unixdict.txt")

DICT letters create
MODE {}
COMPILE
LOOP word=words
letters=SPLIT (word,|":?:")
LOOP letter=letters
ENDLOOP
ENDLOOP
ENDCOMPILE

index    =DIGIT_INDEX (cnt)
index    =REVERSE (index)
letter   =INDEX_SORT (letter,index)
cnt      =INDEX_SORT (cnt,index)
frequency=JOIN (letter," --- ",cnt)

*{frequency}```

Output:

```e --- 20144
a --- 16421
i --- 13980
r --- 13436
t --- 12836
o --- 12738
n --- 12097
s --- 10210
l --- 10061
c --- 8216
u --- 6489
m --- 5828
d --- 5799
p --- 5516
h --- 5208
g --- 4129
b --- 4115
y --- 3633
f --- 2662
w --- 1968
k --- 1925
v --- 1902
x --- 617
z --- 433
j --- 430
q --- 378
' --- 105
. --- 6
& --- 6
1 --- 2
9 --- 1
8 --- 1
7 --- 1
6 --- 1
5 --- 1
4 --- 1
3 --- 1
2 --- 1
0 --- 1
```

## TXR

### TXR Extraction Language plus TXR Lisp

```@(do (defvar h (hash :equal-based)))
@(repeat)
@(coll :vars ())@\
@{letter /[A-Za-z]/}@(filter :upcase letter)@\
@(do (inc [h letter 0]))@\
@(end)
@(end)
@(do (dohash (key value h)
(format t "~a: ~a\n" key value)))```
Output:
```\$ ./txr letterfreq.txr /usr/share/dict/words
A: 64123
B: 15524
C: 31569
[ ... abridged ... ]
X: 2124
Y: 12507
Z: 3238```

### TXR Lisp

```(let* ((s (open-file "/usr/share/dict/words" "r"))
(chrs [keep-if* chr-isalpha (gun (get-char s))])
(h [group-reduce (hash) chr-toupper (op succ @1) chrs 0]))
(dohash (key value h)
(put-line `@key: @value`)))```

## Vala

Library: Gee

Counts every character except new line character.

```using Gee;

void main(string[] args){
string filename = args;
var file = FileStream.open(filename, "r");

var	counter	= new HashMap<char, int>();

while (line != null){
for (int x = 0;	x < line.length; x++){
counter[line[x]] = counter[line[x]] + 1;
}
}

foreach (var elem in counter.entries){
stdout.printf("%c occured %d times\n", elem.key, elem.value);
}
}
```

Sample output (run on its own source code) with several lines omitted:

```v occured 5 times
, occured 4 times
w occured 2 times
occured 19 times
S occured 1 times
1 occured 2 times
! occured 1 times
k occured 1 times
l occured 22 times
```

## VBA

```Public Sub LetterFrequency(fname)
'count number of letters in text file "fname" (ASCII-coded)
'note: we count all characters but print only the letter frequencies

Dim Freqs(255) As Long
Dim abyte As Byte
Dim ascal as Byte 'ascii code for lowercase a
Dim ascau as Byte 'ascii code for uppercase a

'try to open the file
On Error GoTo CantOpen
Open fname For Input As #1
On Error GoTo 0

'initialize
For i = 0 To 255
Freqs(i) = 0
Next i

'process file byte-per-byte
While Not EOF(1)
abyte = Asc(Input(1, #1))
Freqs(abyte) = Freqs(abyte) + 1
Wend
Close #1

'add lower and upper case together and print result
Debug.Print "Frequencies:"
ascal = Asc("a")
ascau = Asc("A")
For i = 0 To 25
Debug.Print Chr\$(ascal + i), Freqs(ascal + i) + Freqs(ascau + i)
Next i
Exit Sub

CantOpen:
Debug.Print "can't find or read the file "; fname
Close
End Sub```

Output:

```LetterFrequency "d:\largetext.txt"
Frequencies:
a              24102
b              4985
c              4551
d              19127
e              61276
f              2734
g              10661
h              8243
i              21589
j              4904
k              7186
l              12026
m              7454
n              31963
o              19021
p              4960
q              37
r              21166
s              13403
t              21090
u              6117
v              8612
w              5017
x              168
y              299
z              4159
```

## VBScript

```filepath = "SPECIFY FILE PATH HERE"

Set objfso = CreateObject("Scripting.FileSystemObject")
Set objdict = CreateObject("Scripting.Dictionary")
Set objfile = objfso.OpenTextFile(filepath,1)

For i = 1 To Len(txt)
char = Mid(txt,i,1)
If objdict.Exists(char) Then
objdict.Item(char) = objdict.Item(char) + 1
Else
End If
Next

For Each key In objdict.Keys
WScript.StdOut.WriteLine key & " = " & objdict.Item(key)
Next

objfile.Close
Set objfso = Nothing
Set objdict = Nothing```

## Vedit macro language

```File_Open("c:\txt\a_text_file.txt")
Update()

for (#1='A'; #1<='Z'; #1++) {
Out_Reg(103) Char_Dump(#1,NOCR) Out_Reg(CLEAR)
#2 = Search(@103, BEGIN+ALL+NOERR)
Message(@103) Num_Type(#2)
}```

Example output:

```A   76
B   23
C   51
D   64
E  192
F   51
G   32
H   59
I  146
J    1
K    9
L   73
M   34
N   94
O  113
P   27
Q    1
R   92
S   89
T  138
U   63
V   26
W   35
X   16
Y   16
Z    2
```

## V (Vlang)

```import os
struct LetterFreq {
rune int
freq int
}

fn main(){
mut freq := map[rune]int{}
for c in file {
freq[c]++
}
mut lf := []LetterFreq{}
for k,v in freq {
lf << LetterFreq{u8(k),v}
}
lf.sort_with_compare(fn(a &LetterFreq, b &LetterFreq)int{
if a.freq > b.freq {
return -1
}
if a.freq < b.freq {
return 1
}
return 0
})
for f in lf {
println('\${u8(f.rune).ascii_str()} \${f.rune} \$f.freq')
}
}```
Output:
``` D 25103

A 25103
e 65 20144
a 61 16421
i 69 13980
r 72 13436
t 74 12836
o 6F 12738
n 6E 12097
s 73 10210
l 6C 10061
c 63 8216
u 75 6489
m 6D 5828
d 64 5799
p 70 5516
h 68 5208
g 67 4129
b 62 4115
y 79 3633
f 66 2662
w 77 1968
k 6B 1925
v 76 1902
x 78 617
z 7A 433
j 6A 430
q 71 378
' 27 105
& 26 6
. 2E 6
1 31 2
8 38 1
7 37 1
6 36 1
5 35 1
4 34 1
3 33 1
2 32 1
0 30 1
9 39 1
```

## Whitespace

```push 127
; Initialize a slot in the heap for each ASCII character.
0:
dup
push 0
store
push 1
sub
dup
jn 1
jump 0
; Read until EOF, incrementing the relevant heap slot.
1:
push 0
dup
ichr
dup
jn 2 ; Done reading, proceed to print.
dup
push 1
store
jump 1
; Stack is [-1 -1], but  would be nice.
2:
sub
; Print characters with tallies greater than 0.
3:
push 1
dup
push 128
sub
jz 4 ; All done.
dup
jz 3 ; Don't print if no occurrences.
dup
ochr ; Display the character,
push 32
ochr ; a space,
dup
onum ; its frequency,
push 10
ochr ; and a newline.
jump 3
4:
pop
exit
```
Output:
```\$ cat freq.ws | wspace freq.ws
64

55
119```

## Wren

Library: Wren-fmt

As we have a copy to hand, we count the number of letters in the MIT 10000 word list which apparently contains nothing other than lower case letters.

```import "io" for File
import "/fmt" for Fmt

var freqs = List.filled(26, 0)
for (c in text.codePoints) {
if (c >= 97 && c <= 122) {
freqs[c-97] = freqs[c-97] + 1
}
}
var totalFreq = freqs.reduce { |sum, f| sum + f }
System.print("Frequencies of letters in mit10000.txt:")
System.print("\n    freq     \%")
System.print("----------------")

for (i in 0..25) {
Fmt.print("\$c  \$5d  \$6.2f", i+97, freqs[i], freqs[i]/totalFreq * 100)
}
System.print("   -----  ------")
Fmt.print("   \$5d  100.00", totalFreq)

Fmt.print("\nTotal characters in text file = \$d minus 10000 \\n's = \$d", text.count, totalFreq)```
Output:
```Frequencies of letters in mit10000.txt:

freq     %
----------------
a   5378    8.16
b   1141    1.73
c   3025    4.59
d   2507    3.81
e   7601   11.54
f    927    1.41
g   1717    2.61
h   1429    2.17
i   5461    8.29
j    183    0.28
k    592    0.90
l   3231    4.90
m   1912    2.90
n   4822    7.32
o   4252    6.45
p   2027    3.08
q    123    0.19
r   4860    7.38
s   5085    7.72
t   4760    7.23
u   1939    2.94
v    849    1.29
w    632    0.96
x    264    0.40
y   1027    1.56
z    136    0.21
-----  ------
65880  100.00

Total characters in text file = 75880 minus 10000 \n's = 65880
```

## XPL0

This takes advantage of DOS's ability to redirect input from a file to the keyboard. The input file must be terminated with an end-of-file character (\$1A). Usage: count <filename.ext

```include c:\cxpl\codes;          \intrinsic 'code' declarations
int A(256), C, I;
[for C:= 0 to 256-1 do A(C):= 0;
repeat  C:= ChIn(1);            \device 1 doesn't buffer nor echo chars
A(C):= A(C)+1;          \count character
until   C=\EOF\\$1A;
C:= 0;
for I:= 0 to 128-1 do           \only show 7-bit ASCII
[ChOut(0, \tab\9);
case C of
\$0A: ChOut(6, \$19);   \line feed = down arrow
\$0D: ChOut(6, \$1B)    \carriage return = left arrow
other  ChOut(6, C);     \all other characters display on device 6
ChOut(0, ^ );
IntOut(0, A(C));        \show count
C:= C+16;               \columnar order
if (I&7) = 7 then [CrLf(0);  C:= C-8*16+1];
];
]```

Example output of count.xpl counting itself: ## Yabasic

```dim ascCodes(255)

f = open("unixdict.txt", "r")

if f then
while(not eof(#f))
line input #f a\$
for i = 1 to len(a\$)
c = asc(mid\$(a\$, i, 1))
ascCodes(c) = ascCodes(c) + 1
next
wend
for i = 1 to 255
c = ascCodes(i)
if c print chr\$(i), " = ", c
next
close #f
end if```

## zkl

```fcn ccnt(textInBitBucket){
letters:=["a".."z"].pump(List().write,0); // array of 26 zeros
textInBitBucket.howza(0).pump(Void,'wrap(c){  // pump text as ints
if(97<=c<=122)     c-=97;
else if(65<=c<=90) c-=65;
else return(Void.Skip);
letters[c]+=1
});
sum:=letters.sum(); println(sum," letters");
letters.enumerate().pump(List,'wrap([(c,n)]){
"%s(%d:%d%)".fmt((c+65).toChar(),n,n*100/sum)})
.concat(",").println();
}

ccnt(Data(0,Int,"This is a test"));
Output:
```11 letters
A(1:9%),B(0:0%),C(0:0%),D(0:0%),E(1:9%),F(0:0%),G(0:0%),H(1:9%),I(2:18%),J(0:0%),K(0:0%),L(0:0%),M(0:0%),N(0:0%),O(0:0%),P(0:0%),Q(0:0%),R(0:0%),S(3:27%),T(3:27%),U(0:0%),V(0:0%),W(0:0%),X(0:0%),Y(0:0%),Z(0:0%)

181171 letters
A(16421:9%),B(4115:2%),C(8216:4%),D(5799:3%),E(20144:11%),F(2662:1%),G(4129:2%),H(5208:2%),I(13980:7%),J(430:0%),K(1925:1%),L(10061:5%),M(5828:3%),N(12097:6%),O(12738:7%),P(5516:3%),Q(378:0%),R(13436:7%),S(10210:5%),T(12836:7%),U(6489:3%),V(1902:1%),W(1968:1%),X(617:0%),Y(3633:2%),Z(433:0%)
```

## Zoea

```program: letter_frequency
input: 'cbcacb'                  # can be literal value, stdin or file url at runtime
derive: [[a,1],[b,2],[c,3]]
output: 'a : 1\nb : 2\nc : 3\n'```