String matching
You are encouraged to solve this task according to the task description, using any language you may know.
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operations
Concatenation |
Interpolation |
Comparison |
Matching
Memory Operations
Pointers & references |
Addresses
- Task
Given two strings, demonstrate the following three types of string matching:
- Determining if the first string starts with second string
- Determining if the first string contains the second string at any location
- Determining if the first string ends with the second string
Optional requirements:
- Print the location of the match for part 2
- Handle multiple occurrences of a string for part 2.
Other tasks related to string operations:
- Metrics
- Counting
- Word frequency
- Letter frequency
- Jewels and stones
- I before E except after C
- Bioinformatics/base count
- Count occurrences of a substring
- Count how many vowels and consonants occur in a string
- Remove/replace
- XXXX redacted
- Conjugate a Latin verb
- Remove vowels from a string
- String interpolation (included)
- Strip block comments
- Strip comments from a string
- Strip a set of characters from a string
- Strip whitespace from a string -- top and tail
- Strip control codes and extended characters from a string
- Anagrams/Derangements/shuffling
- Word wheel
- ABC problem
- Sattolo cycle
- Knuth shuffle
- Ordered words
- Superpermutation minimisation
- Textonyms (using a phone text pad)
- Anagrams
- Anagrams/Deranged anagrams
- Permutations/Derangements
- Find/Search/Determine
- ABC words
- Odd words
- Word ladder
- Semordnilap
- Word search
- Wordiff (game)
- String matching
- Tea cup rim text
- Alternade words
- Changeable words
- State name puzzle
- String comparison
- Unique characters
- Unique characters in each string
- Extract file extension
- Levenshtein distance
- Palindrome detection
- Common list elements
- Longest common suffix
- Longest common prefix
- Compare a list of strings
- Longest common substring
- Find common directory path
- Words from neighbour ones
- Change e letters to i in words
- Non-continuous subsequences
- Longest common subsequence
- Longest palindromic substrings
- Longest increasing subsequence
- Words containing "the" substring
- Sum of the digits of n is substring of n
- Determine if a string is numeric
- Determine if a string is collapsible
- Determine if a string is squeezable
- Determine if a string has all unique characters
- Determine if a string has all the same characters
- Longest substrings without repeating characters
- Find words which contains all the vowels
- Find words which contain the most consonants
- Find words which contains more than 3 vowels
- Find words whose first and last three letters are equal
- Find words with alternating vowels and consonants
- Formatting
- Substring
- Rep-string
- Word wrap
- String case
- Align columns
- Literals/String
- Repeat a string
- Brace expansion
- Brace expansion using ranges
- Reverse a string
- Phrase reversals
- Comma quibbling
- Special characters
- String concatenation
- Substring/Top and tail
- Commatizing numbers
- Reverse words in a string
- Suffixation of decimal numbers
- Long literals, with continuations
- Numerical and alphabetical suffixes
- Abbreviations, easy
- Abbreviations, simple
- Abbreviations, automatic
- Song lyrics/poems/Mad Libs/phrases
- Mad Libs
- Magic 8-ball
- 99 bottles of beer
- The Name Game (a song)
- The Old lady swallowed a fly
- The Twelve Days of Christmas
- Tokenize
- Text between
- Tokenize a string
- Word break problem
- Tokenize a string with escaping
- Split a character string based on change of character
- Sequences
11l
print(‘abcd’.starts_with(‘ab’))
print(‘abcd’.ends_with(‘zn’))
print(‘bb’ C ‘abab’)
print(‘ab’ C ‘abab’)
print(‘abab’.find(‘bb’) ? -1)
print(‘abab’.find(‘ab’) ? -1)- Output:
1B 0B 0B 1B -1 0
360 Assembly
* String matching 04/04/2017
STRMATCH CSECT
USING STRMATCH,R15
XPRNT SS,L'SS
*
CLC SS(L'S1),S1
BNE NOT1
XPRNT =C'-- STARTS WITH',14
XPRNT S1,L'S1
NOT1 EQU *
*
CLC SS+L'SS-L'S2(L'S2),S2
BNE NOT2
XPRNT =C'-- ENDS WITH',12
XPRNT S2,L'S2
NOT2 EQU *
*
LA R0,L'SS-L'S3+1
LA R1,SS
LOOP CLC 0(L'S3,R1),S3
BNE NOT3
XPRNT =C'-- CONTAINS',11
XPRNT S3,L'S3
NOT3 LA R1,1(R1)
BCT R0,LOOP
*
BR R14
SS DC CL6'ABCDEF'
S1 DC CL2'AB'
S2 DC CL2'EF'
S3 DC CL2'CD'
PG DC CL80' '
YREGS
END STRMATCH- Output:
ABCDEF -- STARTS WITH AB -- ENDS WITH EF -- CONTAINS CD
AArch64 Assembly
/* ARM assembly AARCH64 Raspberry PI 3B */
/* program strMatching64.s */
/*******************************************/
/* Constantes file */
/*******************************************/
/* for this file see task include a file in language AArch64 assembly*/
.include "../includeConstantesARM64.inc"
/*******************************************/
/* Initialized data */
/*******************************************/
.data
szMessFound: .asciz "String found. \n"
szMessNotFound: .asciz "String not found. \n"
szString: .asciz "abcdefghijklmnopqrstuvwxyz"
szString2: .asciz "abc"
szStringStart: .asciz "abcd"
szStringEnd: .asciz "xyz"
szStringStart2: .asciz "abcd"
szStringEnd2: .asciz "xabc"
szCarriageReturn: .asciz "\n"
/*******************************************/
/* UnInitialized data */
/*******************************************/
.bss
/*******************************************/
/* code section */
/*******************************************/
.text
.global main
main:
ldr x0,qAdrszString // address input string
ldr x1,qAdrszStringStart // address search string
bl searchStringDeb // Determining if the first string starts with second string
cmp x0,0
ble 1f
ldr x0,qAdrszMessFound // display message
bl affichageMess
b 2f
1:
ldr x0,qAdrszMessNotFound
bl affichageMess
2:
ldr x0,qAdrszString // address input string
ldr x1,qAdrszStringEnd // address search string
bl searchStringFin // Determining if the first string ends with the second string
cmp x0,0
ble 3f
ldr x0,qAdrszMessFound // display message
bl affichageMess
b 4f
3:
ldr x0,qAdrszMessNotFound
bl affichageMess
4:
ldr x0,qAdrszString2 // address input string
ldr x1,qAdrszStringStart2 // address search string
bl searchStringDeb //
cmp x0,0
ble 5f
ldr x0,qAdrszMessFound // display message
bl affichageMess
b 6f
5:
ldr x0,qAdrszMessNotFound
bl affichageMess
6:
ldr x0,qAdrszString2 // address input string
ldr x1,qAdrszStringEnd2 // address search string
bl searchStringFin
cmp x0,0
ble 7f
ldr x0,qAdrszMessFound // display message
bl affichageMess
b 8f
7:
ldr x0,qAdrszMessNotFound
bl affichageMess
8:
ldr x0,qAdrszString // address input string
ldr x1,qAdrszStringEnd // address search string
bl searchSubString // Determining if the first string contains the second string at any location
cmp x0,0
ble 9f
ldr x0,qAdrszMessFound // display message
bl affichageMess
b 10f
9:
ldr x0,qAdrszMessNotFound // display substring result
bl affichageMess
10:
100: // standard end of the program
mov x0,0 // return code
mov x8,EXIT // request to exit program
svc 0 // perform system call
qAdrszMessFound: .quad szMessFound
qAdrszMessNotFound: .quad szMessNotFound
qAdrszString: .quad szString
qAdrszString2: .quad szString2
qAdrszStringStart: .quad szStringStart
qAdrszStringEnd: .quad szStringEnd
qAdrszStringStart2: .quad szStringStart2
qAdrszStringEnd2: .quad szStringEnd2
qAdrszCarriageReturn: .quad szCarriageReturn
/******************************************************************/
/* search substring at begin of input string */
/******************************************************************/
/* x0 contains the address of the input string */
/* x1 contains the address of substring */
/* x0 returns 1 if find or 0 if not or -1 if error */
searchStringDeb:
stp x1,lr,[sp,-16]! // save registers
stp x2,x3,[sp,-16]! // save registers
mov x3,0 // counter byte string
ldrb w4,[x1,x3] // load first byte of substring
cbz x4,99f // empty string ?
1:
ldrb w2,[x0,x3] // load byte string input
cbz x2,98f // zero final ?
cmp x4,x2 // bytes equals ?
bne 98f // no not find
add x3,x3,1 // increment counter
ldrb w4,[x1,x3] // and load next byte of substring
cbnz x4,1b // zero final ?
mov x0,1 // yes is ok
b 100f
98:
mov x0,0 // not find
b 100f
99:
mov x0,-1 // error
100:
ldp x2,x3,[sp],16 // restaur 2 registers
ldp x1,lr,[sp],16 // restaur 2 registers
ret // return to address lr x30
/******************************************************************/
/* search substring at end of input string */
/******************************************************************/
/* x0 contains the address of the input string */
/* x1 contains the address of substring */
/* x0 returns 1 if find or 0 if not or -1 if error */
searchStringFin:
stp x1,lr,[sp,-16]! // save registers
stp x2,x3,[sp,-16]! // save registers
stp x4,x5,[sp,-16]! // save registers
mov x3,0 // counter byte string
// search the last character of substring
1:
ldrb w4,[x1,x3] // load byte of substring
cmp x4,#0 // zero final ?
add x2,x3,1
csel x3,x2,x3,ne // no increment counter
//addne x3,#1 // no increment counter
bne 1b // and loop
cbz x3,99f // empty string ?
sub x3,x3,1 // index of last byte
ldrb w4,[x1,x3] // load last byte of substring
// search the last character of string
mov x2,0 // index last character
2:
ldrb w5,[x0,x2] // load first byte of substring
cmp x5,0 // zero final ?
add x5,x2,1 // no -> increment counter
csel x2,x5,x2,ne
//addne x2,#1 // no -> increment counter
bne 2b // and loop
cbz x2,98f // empty input string ?
sub x2,x2,1 // index last character
3:
ldrb w5,[x0,x2] // load byte string input
cmp x4,x5 // bytes equals ?
bne 98f // no -> not found
subs x3,x3,1 // decrement counter
blt 97f // ok found
subs x2,x2,1 // decrement counter input string
blt 98f // if zero -> not found
ldrb w4,[x1,x3] // load previous byte of substring
b 3b // and loop
97:
mov x0,1 // yes is ok
b 100f
98:
mov x0,0 // not found
b 100f
99:
mov x0,-1 // error
100:
ldp x4,x5,[sp],16 // restaur 2 registers
ldp x2,x3,[sp],16 // restaur 2 registers
ldp x1,lr,[sp],16 // restaur 2 registers
ret // return to address lr x30
/******************************************************************/
/* search a substring in the string */
/******************************************************************/
/* x0 contains the address of the input string */
/* x1 contains the address of substring */
/* x0 returns index of substring in string or -1 if not found */
searchSubString:
stp x1,lr,[sp,-16]! // save registers
stp x2,x3,[sp,-16]! // save registers
stp x4,x5,[sp,-16]! // save registers
mov x2,0 // counter byte input string
mov x3,0 // counter byte string
mov x6,-1 // index found
ldrb w4,[x1,x3]
1:
ldrb w5,[x0,x2] // load byte string
cbz x5,99f // zero final ?
cmp x5,x4 // compare character
beq 2f
mov x6,-1 // no equals - > raz index
mov x3,0 // and raz counter byte
add x2,x2,1 // and increment counter byte
b 1b // and loop
2: // characters equals
cmp x6,-1 // first characters equals ?
csel x6,x2,x6,eq // yes -> index begin in x6
//moveq x6,x2 // yes -> index begin in x6
add x3,x3,1 // increment counter substring
ldrb w4,[x1,x3] // and load next byte
cmp x4,0 // zero final ?
beq 3f // yes -> end search
add x2,x2,1 // else increment counter string
b 1b // and loop
3:
mov x0,x6
b 100f
98:
mov x0,0 // not found
b 100f
99:
mov x0,-1 // error
100:
ldp x4,x5,[sp],16 // restaur 2 registers
ldp x2,x3,[sp],16 // restaur 2 registers
ldp x1,lr,[sp],16 // restaur 2 registers
ret // return to address lr x30
/********************************************************/
/* File Include fonctions */
/********************************************************/
/* for this file see task include a file in language AArch64 assembly */
.include "../includeARM64.inc"Action!
BYTE FUNC FindS(CHAR ARRAY text,sub BYTE start)
BYTE i,j,found
i=start
WHILE i<=text(0)-sub(0)+1
DO
found=0
FOR j=1 TO sub(0)
DO
IF text(i+j-1)#sub(j) THEN
found=0 EXIT
ELSE
found=1
FI
OD
IF found THEN
RETURN (i)
FI
i==+1
OD
RETURN (0)
BYTE FUNC StartsWith(CHAR ARRAY text,sub)
BYTE pos
pos=FindS(text,sub,1)
IF pos=1 THEN
RETURN (1)
FI
RETURN (0)
BYTE FUNC EndsWith(CHAR ARRAY text,sub)
BYTE pos,start
IF sub(0)>text(0) THEN
RETURN (0)
FI
start=text(0)-sub(0)+1
pos=FindS(text,sub,start)
IF pos=start THEN
RETURN (1)
FI
RETURN (0)
BYTE FUNC Contains(CHAR ARRAY text,sub
BYTE ARRAY positions)
BYTE pos,count
pos=1 count=0
WHILE pos<=text(0)
DO
pos=FindS(text,sub,pos)
IF pos>0 THEN
positions(count)=pos
count==+1
pos==+1
ELSE
EXIT
FI
OD
RETURN (count)
PROC TestStartsWith(CHAR ARRAY text,sub)
IF StartsWith(text,sub) THEN
PrintF("""%S"" starts with ""%S"".%E",text,sub)
ELSE
PrintF("""%S"" does not start with ""%S"".%E",text,sub)
FI
RETURN
PROC TestEndsWith(CHAR ARRAY text,sub)
IF EndsWith(text,sub) THEN
PrintF("""%S"" ends with ""%S"".%E",text,sub)
ELSE
PrintF("""%S"" does not end with ""%S"".%E",text,sub)
FI
RETURN
PROC TestContains(CHAR ARRAY text,sub)
BYTE ARRAY positions(20)
BYTE i,count
count=Contains(text,sub,positions)
IF count>0 THEN
PrintF("""%S"" contains %B ""%S"" at positions:",text,count,sub)
FOR i=0 TO count-1
DO
PrintB(positions(i))
IF i<count-1 THEN
Print(", ")
ELSE
PrintE(".")
FI
OD
ELSE
PrintF("""%S"" does not contain ""%S"".%E",text,sub)
FI
RETURN
PROC Main()
TestStartsWith("1234abc","123")
TestStartsWith("1234abc","234")
PutE()
TestContains("abbaabab","ab")
TestContains("abbaabab","ba")
TestContains("abbaabab","xyz")
PutE()
TestEndsWith("1234abc","abc")
TestEndsWith("1234abc","ab")
RETURN- Output:
Screenshot from Atari 8-bit computer
"1234abc" starts with "123". "1234abc" does not start with "234". "abbaabab" contains 3 "ab" at positions:1, 5, 7. "abbaabab" contains 2 "ba" at positions:3, 6. "abbaabab" does not contain "xyz". "1234abc" ends with "abc". "1234abc" does not end with "ab".
Ada
with Ada.Strings.Fixed; use Ada.Strings.Fixed;
with Ada.Text_IO; use Ada.Text_IO;
procedure Match_Strings is
S1 : constant String := "abcd";
S2 : constant String := "abab";
S3 : constant String := "ab";
begin
if S1'Length >= S3'Length and then S1 (S1'First..S1'First + S3'Length - 1) = S3 then
Put_Line (''' & S1 & "' starts with '" & S3 & ''');
end if;
if S2'Length >= S3'Length and then S2 (S2'Last - S3'Length + 1..S2'Last) = S3 then
Put_Line (''' & S2 & "' ends with '" & S3 & ''');
end if;
Put_Line (''' & S3 & "' first appears in '" & S1 & "' at" & Integer'Image (Index (S1, S3)));
Put_Line
( ''' & S3 & "' appears in '" & S2 & ''' &
Integer'Image (Ada.Strings.Fixed.Count (S2, S3)) & " times"
);
end Match_Strings;
- Output:
'abcd' starts with 'ab' 'abab' ends with 'ab' 'ab' first appears in 'abcd' at 1 'ab' appears in 'abab' 2 times
Aime
text t;
data b;
b = "Bangkok";
t = "Bang";
o_form("starts with, embeds, ends with \"~\": ~, ~, ~\n", t, b.seek(t) == 0,
b.seek(t) != -1,
b.seek(t) != -1 && b.seek(t) + ~t == ~b);
t = "ok";
o_form("starts with, embeds, ends with \"~\": ~, ~, ~\n", t, b.seek(t) == 0,
b.seek(t) != -1,
b.seek(t) != -1 && b.seek(t) + ~t == ~b);
t = "Summer";
o_form("starts with, embeds, ends with \"~\": ~, ~, ~\n", t, b.seek(t) == 0,
b.seek(t) != -1,
b.seek(t) != -1 && b.seek(t) + ~t == ~b);- Output:
starts with, embeds, ends with "Bang": 1, 1, 0 starts with, embeds, ends with "ok": 0, 1, 1 starts with, embeds, ends with "Summer": 0, 0, 0
ALGOL 68
# define some appropriate OPerators #
PRIO STARTSWITH = 5, ENDSWITH = 5;
OP STARTSWITH = (STRING str, prefix)BOOL: # assuming LWB = 1 #
IF UPB str < UPB prefix THEN FALSE ELSE str[:UPB prefix]=prefix FI;
OP ENDSWITH = (STRING str, suffix)BOOL: # assuming LWB = 1 #
IF UPB str < UPB suffix THEN FALSE ELSE str[UPB str-UPB suffix+1:]=suffix FI;
INT loc, loc2;
print((
"abcd" STARTSWITH "ab", # returns TRUE #
"abcd" ENDSWITH "zn", # returns FALSE #
string in string("bb",loc,"abab"), # returns FALSE #
string in string("ab",loc,"abab"), # returns TRUE #
(string in string("bb",loc,"abab")|loc|-1), # returns -1 #
(string in string("ab",loc,"abab")|loc|-1), # returns +1 #
(string in string("ab",loc2,"abab"[loc+1:])|loc+loc2|-1) # returns +3 #
))- Output:
TFFT -1 +1 +3
AppleScript
set stringA to "I felt happy because I saw the others were happy and because I knew I should feel happy, but I wasn’t really happy."
set string1 to "I felt happy"
set string2 to "I should feel happy"
set string3 to "I wasn't really happy"
-- Determining if the first string starts with second string
stringA starts with string1 --> true
-- Determining if the first string contains the second string at any location
stringA contains string2 --> true
-- Determining if the first string ends with the second string
stringA ends with string3 --> false
-- Print the location of the match for part 2
offset of string2 in stringA --> 69
AppleScript doesn't have a builtin means of matching multiple occurrences of a substring, however one can redefine the existing offset command to add this functionality:
-- Handle multiple occurrences of a string for part 2
on offset of needle in haystack
local needle, haystack
if the needle is not in the haystack then return {}
set my text item delimiters to the needle
script
property N : needle's length
property t : {1 - N} & haystack's text items
end script
tell the result
repeat with i from 2 to (its t's length) - 1
set x to item i of its t
set y to item (i - 1) of its t
set item i of its t to (its N) + (x's length) + y
end repeat
items 2 thru -2 of its t
end tell
end offset
offset of "happy" in stringA --> {8, 44, 83, 110}
or, defining an offsets function in terms of a more general findIndices:
-- offsets :: String -> String -> [Int]
on offsets(needle, haystack)
script match
property mx : length of haystack
property d : (length of needle) - 1
on |λ|(x, i, xs)
set z to d + i
mx ≥ z and needle = text i thru z of xs
end |λ|
end script
findIndices(match, haystack)
end offsets
-- TEST ---------------------------------------------------
on run
set txt to "I felt happy because I saw the others " & ¬
"were happy and because I knew I should " & ¬
"feel happy, but I wasn’t really happy."
offsets("happy", txt)
--> {8, 44, 83, 110}
end run
-- GENERIC -------------------------------------------------
-- 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
-- findIndices :: (a -> Bool) -> [a] -> [Int]
-- findIndices :: (String -> Bool) -> String -> [Int]
on findIndices(p, xs)
script go
property f : mReturn(p)
on |λ|(x, i, xs)
if f's |λ|(x, i, xs) then
{i}
else
{}
end if
end |λ|
end script
concatMap(go, xs)
end findIndices
-- Lift 2nd class handler function into 1st class script wrapper
-- mReturn :: First-class m => (a -> b) -> m (a -> b)
on mReturn(f)
if script is class of f then
f
else
script
property |λ| : f
end script
end if
end mReturn
- Output:
{8, 44, 83, 110}
ARM Assembly
/* ARM assembly Raspberry PI */
/* program strMatching.s */
/* Constantes */
.equ STDOUT, 1 @ Linux output console
.equ EXIT, 1 @ Linux syscall
.equ WRITE, 4 @ Linux syscall
/* Initialized data */
.data
szMessFound: .asciz "String found. \n"
szMessNotFound: .asciz "String not found. \n"
szString: .asciz "abcdefghijklmnopqrstuvwxyz"
szString2: .asciz "abc"
szStringStart: .asciz "abcd"
szStringEnd: .asciz "xyz"
szStringStart2: .asciz "abcd"
szStringEnd2: .asciz "xabc"
szCarriageReturn: .asciz "\n"
/* UnInitialized data */
.bss
/* code section */
.text
.global main
main:
ldr r0,iAdrszString @ address input string
ldr r1,iAdrszStringStart @ address search string
bl searchStringDeb @ Determining if the first string starts with second string
cmp r0,#0
ble 1f
ldr r0,iAdrszMessFound @ display message
bl affichageMess
b 2f
1:
ldr r0,iAdrszMessNotFound
bl affichageMess
2:
ldr r0,iAdrszString @ address input string
ldr r1,iAdrszStringEnd @ address search string
bl searchStringFin @ Determining if the first string ends with the second string
cmp r0,#0
ble 3f
ldr r0,iAdrszMessFound @ display message
bl affichageMess
b 4f
3:
ldr r0,iAdrszMessNotFound
bl affichageMess
4:
ldr r0,iAdrszString2 @ address input string
ldr r1,iAdrszStringStart2 @ address search string
bl searchStringDeb @
cmp r0,#0
ble 5f
ldr r0,iAdrszMessFound @ display message
bl affichageMess
b 6f
5:
ldr r0,iAdrszMessNotFound
bl affichageMess
6:
ldr r0,iAdrszString2 @ address input string
ldr r1,iAdrszStringEnd2 @ address search string
bl searchStringFin
cmp r0,#0
ble 7f
ldr r0,iAdrszMessFound @ display message
bl affichageMess
b 8f
7:
ldr r0,iAdrszMessNotFound
bl affichageMess
8:
ldr r0,iAdrszString @ address input string
ldr r1,iAdrszStringEnd @ address search string
bl searchSubString @ Determining if the first string contains the second string at any location
cmp r0,#0
ble 9f
ldr r0,iAdrszMessFound @ display message
bl affichageMess
b 10f
9:
ldr r0,iAdrszMessNotFound @ display substring result
bl affichageMess
10:
100: @ standard end of the program
mov r0, #0 @ return code
mov r7, #EXIT @ request to exit program
svc 0 @ perform system call
iAdrszMessFound: .int szMessFound
iAdrszMessNotFound: .int szMessNotFound
iAdrszString: .int szString
iAdrszString2: .int szString2
iAdrszStringStart: .int szStringStart
iAdrszStringEnd: .int szStringEnd
iAdrszStringStart2: .int szStringStart2
iAdrszStringEnd2: .int szStringEnd2
iAdrszCarriageReturn: .int szCarriageReturn
/******************************************************************/
/* search substring at begin of input string */
/******************************************************************/
/* r0 contains the address of the input string */
/* r1 contains the address of substring */
/* r0 returns 1 if find or 0 if not or -1 if error */
searchStringDeb:
push {r1-r4,lr} @ save registers
mov r3,#0 @ counter byte string
ldrb r4,[r1,r3] @ load first byte of substring
cmp r4,#0 @ empty string ?
moveq r0,#-1 @ error
beq 100f
1:
ldrb r2,[r0,r3] @ load byte string input
cmp r2,#0 @ zero final ?
moveq r0,#0 @ not find
beq 100f
cmp r4,r2 @ bytes equals ?
movne r0,#0 @ no not find
bne 100f
add r3,#1 @ increment counter
ldrb r4,[r1,r3] @ and load next byte of substring
cmp r4,#0 @ zero final ?
bne 1b @ no -> loop
mov r0,#1 @ yes is ok
100:
pop {r1-r4,lr} @ restaur registers
bx lr @ return
/******************************************************************/
/* search substring at end of input string */
/******************************************************************/
/* r0 contains the address of the input string */
/* r1 contains the address of substring */
/* r0 returns 1 if find or 0 if not or -1 if error */
searchStringFin:
push {r1-r5,lr} @ save registers
mov r3,#0 @ counter byte string
@ search the last character of substring
1:
ldrb r4,[r1,r3] @ load byte of substring
cmp r4,#0 @ zero final ?
addne r3,#1 @ no increment counter
bne 1b @ and loop
cmp r3,#0 @ empty string ?
moveq r0,#-1 @ error
beq 100f
sub r3,#1 @ index of last byte
ldrb r4,[r1,r3] @ load last byte of substring
@ search the last character of string
mov r2,#0 @ index last character
2:
ldrb r5,[r0,r2] @ load first byte of substring
cmp r5,#0 @ zero final ?
addne r2,#1 @ no -> increment counter
bne 2b @ and loop
cmp r2,#0 @ empty input string ?
moveq r0,#0 @ yes -> not found
beq 100f
sub r2,#1 @ index last character
3:
ldrb r5,[r0,r2] @ load byte string input
cmp r4,r5 @ bytes equals ?
movne r0,#0 @ no -> not found
bne 100f
subs r3,#1 @ decrement counter
movlt r0,#1 @ if zero -> ok found
blt 100f
subs r2,#1 @ decrement counter input string
movlt r0,#0 @ if zero -> not found
blt 100f
ldrb r4,[r1,r3] @ load previous byte of substring
b 3b @ and loop
100:
pop {r1-r5,lr} @ restaur registers
bx lr @ return
/******************************************************************/
/* search a substring in the string */
/******************************************************************/
/* r0 contains the address of the input string */
/* r1 contains the address of substring */
/* r0 returns index of substring in string or -1 if not found */
searchSubString:
push {r1-r6,lr} @ save registers
mov r2,#0 @ counter byte input string
mov r3,#0 @ counter byte string
mov r6,#-1 @ index found
ldrb r4,[r1,r3]
1:
ldrb r5,[r0,r2] @ load byte string
cmp r5,#0 @ zero final ?
moveq r0,#-1 @ yes returns error
beq 100f
cmp r5,r4 @ compare character
beq 2f
mov r6,#-1 @ no equals - > raz index
mov r3,#0 @ and raz counter byte
add r2,#1 @ and increment counter byte
b 1b @ and loop
2: @ characters equals
cmp r6,#-1 @ first characters equals ?
moveq r6,r2 @ yes -> index begin in r6
add r3,#1 @ increment counter substring
ldrb r4,[r1,r3] @ and load next byte
cmp r4,#0 @ zero final ?
beq 3f @ yes -> end search
add r2,#1 @ else increment counter string
b 1b @ and loop
3:
mov r0,r6
100:
pop {r1-r6,lr} @ restaur registers
bx lr
/******************************************************************/
/* display text with size calculation */
/******************************************************************/
/* r0 contains the address of the message */
affichageMess:
push {r0,r1,r2,r7,lr} @ save registers
mov r2,#0 @ counter length */
1: @ loop length calculation
ldrb r1,[r0,r2] @ read octet start position + index
cmp r1,#0 @ if 0 its over
addne r2,r2,#1 @ else add 1 in the length
bne 1b @ and loop
@ so here r2 contains the length of the message
mov r1,r0 @ address message in r1
mov r0,#STDOUT @ code to write to the standard output Linux
mov r7, #WRITE @ code call system "write"
svc #0 @ call system
pop {r0,r1,r2,r7,lr} @ restaur registers
bx lr @ returnArturo
print prefix? "abcd" "ab"
print prefix? "abcd" "cd"
print suffix? "abcd" "ab"
print suffix? "abcd" "cd"
print contains? "abcd" "ab"
print contains? "abcd" "xy"
print in? "ab" "abcd"
print in? "xy" "abcd"
print index "abcd" "bc"
print index "abcd" "xy"
- Output:
true false false true true false true false 1 null
AutoHotkey
String1 = abcd
String2 = abab
If (SubStr(String1,1,StrLen(String2)) = String2)
MsgBox, "%String1%" starts with "%String2%".
IfInString, String1, %String2%
{
Position := InStr(String1,String2)
StringReplace, String1, String1, %String2%, %String2%, UseErrorLevel
MsgBox, "%String1%" contains "%String2%" at position %Position%`, and appears %ErrorLevel% times.
}
StringRight, TempVar, String1, StrLen(String2)
If TempVar = %String2%
MsgBox, "%String1%" ends with "%String2%".
AutoIt
$string1 = "arduinoardblobard"
$string2 = "ard"
; == Determining if the first string starts with second string
If StringLeft($string1, StringLen($string2)) = $string2 Then
ConsoleWrite("1st string starts with 2nd string." & @CRLF)
Else
ConsoleWrite("1st string does'nt starts with 2nd string." & @CRLF)
EndIf
; == Determining if the first string contains the second string at any location
; == Print the location of the match for part 2
; == Handle multiple occurrences of a string for part 2
$start = 1
$count = 0
$pos = StringInStr($string1, $string2)
While $pos
$count += 1
ConsoleWrite("1st string contains 2nd string at position: " & $pos & @CRLF)
$pos = StringInStr($string1, $string2, 0, 1, $start + $pos + StringLen($string2))
WEnd
If $count = 0 Then ConsoleWrite("1st string does'nt contain 2nd string." & @CRLF)
; == Determining if the first string ends with the second string
If StringRight($string1, StringLen($string2)) = $string2 Then
ConsoleWrite("1st string ends with 2nd string." & @CRLF)
Else
ConsoleWrite("1st string does'nt ends with 2nd string." & @CRLF)
EndIf
AWK
#!/usr/bin/awk -f
{ pos=index($2,$1)
print $2, (pos==1 ? "begins" : "does not begin" ), "with " $1
print $2, (pos ? "contains an" : "does not contain" ), "\"" $1 "\""
if (pos) {
l=length($1)
Pos=pos
s=$2
while (Pos){
print " " $1 " is at index", x+Pos
x+=Pos
s=substr(s,Pos+l)
Pos=index(s,$1)
}
}
print $2, (substr($2,pos)==$1 ? "ends" : "does not end"), "with " $1
}
BASIC
first$ = "qwertyuiop"
'Determining if the first string starts with second string
second$ = "qwerty"
IF LEFT$(first$, LEN(second$)) = second$ THEN
PRINT "'"; first$; "' starts with '"; second$; "'"
ELSE
PRINT "'"; first$; "' does not start with '"; second$; "'"
END IF
'Determining if the first string contains the second string at any location
'Print the location of the match for part 2
second$ = "wert"
x = INSTR(first$, second$)
IF x THEN
PRINT "'"; first$; "' contains '"; second$; "' at position "; x
ELSE
PRINT "'"; first$; "' does not contain '"; second$; "'"
END IF
' Determining if the first string ends with the second string
second$ = "random garbage"
IF RIGHT$(first$, LEN(second$)) = second$ THEN
PRINT "'"; first$; "' ends with '"; second$; "'"
ELSE
PRINT "'"; first$; "' does not end with '"; second$; "'"
END IF
- Output:
'qwertyuiop' starts with 'qwerty' 'qwertyuiop' contains 'wert' at position 2 'qwertyuiop' does not end with 'random garbage'
Applesoft BASIC
10 A$ = "THIS, THAT, AND THE OTHER THING"
20 S$ = "TH"
30 DEF FN S(P) = MID$(A$, P, LEN(S$)) = S$
40 PRINT A$ : PRINT
110 S$(1) = "STARTS"
120 S$(0) = "DOES NOT START"
130 PRINT S$(FN S(1))" WITH "S$ : PRINT
210 R$ = "" : FOR I = 1 TO LEN(A$) - LEN(S$) : IF FN S(I) THEN R$ = R$ + STR$(I) + " "
220 NEXT I
230 IF LEN(R$) = 0 THEN PRINT "DOES NOT CONTAIN "S$
240 IF LEN(R$) THEN PRINT "CONTAINS "S$" LOCATED AT POSITION "R$
250 PRINT
310 E$(1) = "ENDS"
320 E$(0) = "DOES NOT END"
330 PRINT E$(FN S(LEN(A$) - LEN(S$) + 1))" WITH "S$Batch File
::NOTE #1: This implementation might crash, or might not work properly if
::you put some of the CMD special characters (ex. %,!, etc) inside the strings.
::
::NOTE #2: The comparisons here are case-SENSITIVE.
::NOTE #3: Spaces in strings are considered.
@echo off
setlocal enabledelayedexpansion
::The main things...
set "str1=qwertyuiop"
set "str2=qwerty"
call :str2_lngth
call :matchbegin
set "str1=qweiuoiocghiioyiocxiisfguiioiuygvd"
set "str2=io"
call :str2_lngth
call :matchcontain
set "str1=blablabla"
set "str2=bbla"
call :str2_lngth
call :matchend
echo.
pause
exit /b 0
::/The main things.
::The functions...
:matchbegin
echo.
if "!str1:~0,%length%!"=="!str2!" (
echo "%str1%" begins with "%str2%".
) else (
echo "%str1%" does not begin with "%str2%".
)
goto :EOF
:matchcontain
echo.
set curr=0&set exist=0
:scanchrloop
if "!str1:~%curr%,%length%!"=="" (
if !exist!==0 echo "%str1%" does not contain "%str2%".
goto :EOF
)
if "!str1:~%curr%,%length%!"=="!str2!" (
echo "%str1%" contains "%str2%". ^(in Position %curr%^)
set exist=1
)
set /a curr+=1&goto scanchrloop
:matchend
echo.
if "!str1:~-%length%!"=="!str2!" (
echo "%str1%" ends with "%str2%".
) else (
echo "%str1%" does not end with "%str2%".
)
goto :EOF
:str2_lngth
set length=0
:loop
if "!str2:~%length%,1!"=="" goto :EOF
set /a length+=1
goto loop
::/The functions.
- Output:
"qwertyuiop" begins with "qwerty". "qweiuoiocghiioyiocxiisfguiioiuygvd" contains "io". (in Position 6) "qweiuoiocghiioyiocxiisfguiioiuygvd" contains "io". (in Position 12) "qweiuoiocghiioyiocxiisfguiioiuygvd" contains "io". (in Position 15) "qweiuoiocghiioyiocxiisfguiioiuygvd" contains "io". (in Position 26) "blablabla" does not end with "bbla". Press any key to continue . . .
BBC BASIC
first$ = "The fox jumps over the dog"
FOR test% = 1 TO 3
READ second$
starts% = FN_first_starts_with_second(first$, second$)
IF starts% PRINT """" first$ """ starts with """ second$ """"
ends% = FN_first_ends_with_second(first$, second$)
IF ends% PRINT """" first$ """ ends with """ second$ """"
where% = FN_first_contains_second_where(first$, second$)
IF where% PRINT """" first$ """ contains """ second$ """ at position " ; where%
howmany% = FN_first_contains_second_howmany(first$, second$)
IF howmany% PRINT """" first$ """ contains """ second$ """ " ; howmany% " time(s)"
NEXT
DATA "The", "he", "dog"
END
DEF FN_first_starts_with_second(A$, B$)
= B$ = LEFT$(A$, LEN(B$))
DEF FN_first_ends_with_second(A$, B$)
= B$ = RIGHT$(A$, LEN(B$))
DEF FN_first_contains_second_where(A$, B$)
= INSTR(A$, B$)
DEF FN_first_contains_second_howmany(A$, B$)
LOCAL I%, N% : I% = 0
REPEAT
I% = INSTR(A$, B$, I%+1)
IF I% THEN N% += 1
UNTIL I% = 0
= N%
- Output:
"The fox jumps over the dog" starts with "The" "The fox jumps over the dog" contains "The" at position 1 "The fox jumps over the dog" contains "The" 1 time(s) "The fox jumps over the dog" contains "he" at position 2 "The fox jumps over the dog" contains "he" 2 time(s) "The fox jumps over the dog" ends with "dog" "The fox jumps over the dog" contains "dog" at position 24 "The fox jumps over the dog" contains "dog" 1 time(s)
BQN
⍷ does much of the heavy lifting here. It is commuted with ˜ so the order of the arguments makes sense.
SW ← ⊑⍷˜
Contains ← ∨´⍷˜
EW ← ¯1⊑⍷˜
Locs ← /⍷˜
- Usage:
"abcd" SW "ab"
1
"abcd" SW "cd"
0
"abcd" EW "ab"
0
"abcd" EW "cd"
1
"abcd" Contains "bb"
0
"abcd" Contains "ab"
1
"abcd" Contains "bc"
1
"abab" Contains "ab"
1
"abab" Locs "ab"
⟨ 0 2 ⟩
Bracmat
Bracmat does pattern matching in expressions subject:pattern and in strings @(subject:pattern). The (sub)pattern ? is a wild card.
( (sentence="I want a number such that that number will be even.")
& out$(@(!sentence:I ?) & "sentence starts with 'I'" | "sentence does not start with 'I'")
& out$(@(!sentence:? such ?) & "sentence contains 'such'" | "sentence does not contain 'such'")
& out$(@(!sentence:? "even.") & "sentence ends with 'even.'" | "sentence does not end with 'even.'")
& 0:?N
& ( @(!sentence:? be (? & !N+1:?N & ~))
| out$str$("sentence contains " !N " occurrences of 'be'")
)
)In the last line, Bracmat is forced by the always failing node ~ to backtrack until all occurrences of 'be' are found.
Thereafter the pattern match expression fails.
The interesting part is the side effect: while backtracking,
the accumulator N keeps track of how many are found.
- Output:
sentence starts with 'I' sentence contains 'such' sentence ends with 'even.' sentence contains 3 occurrences of 'be'
C
Case sensitive matching:
#include <string.h>
#include <stdio.h>
int startsWith(const char* container, const char* target)
{
size_t clen = strlen(container), tlen = strlen(target);
if (clen < tlen)
return 0;
return strncmp(container, target, tlen) == 0;
}
int endsWith(const char* container, const char* target)
{
size_t clen = strlen(container), tlen = strlen(target);
if (clen < tlen)
return 0;
return strncmp(container + clen - tlen, target, tlen) == 0;
}
int doesContain(const char* container, const char* target)
{
return strstr(container, target) != 0;
}
int main(void)
{
printf("Starts with Test ( Hello,Hell ) : %d\n", startsWith("Hello","Hell"));
printf("Ends with Test ( Code,ode ) : %d\n", endsWith("Code","ode"));
printf("Contains Test ( Google,msn ) : %d\n", doesContain("Google","msn"));
return 0;
}
- Output:
Starts with Test ( Hello,Hell ) : 1 Ends with Test ( Code,ode ) : 1 Contains Test ( Google,msn ) : 0
Code without using string library to demonstrate how char strings are just pointers:
#include <stdio.h>
/* returns 0 if no match, 1 if matched, -1 if matched and at end */
int s_cmp(const char *a, const char *b)
{
char c1 = 0, c2 = 0;
while (c1 == c2) {
c1 = *(a++);
if ('\0' == (c2 = *(b++)))
return c1 == '\0' ? -1 : 1;
}
return 0;
}
/* returns times matched */
int s_match(const char *a, const char *b)
{
int i = 0, count = 0;
printf("matching `%s' with `%s':\n", a, b);
while (a[i] != '\0') {
switch (s_cmp(a + i, b)) {
case -1:
printf("matched: pos %d (at end)\n\n", i);
return ++count;
case 1:
printf("matched: pos %d\n", i);
++count;
break;
}
i++;
}
printf("end match\n\n");
return count;
}
int main()
{
s_match("A Short String", "ort S");
s_match("aBaBaBaBa", "aBa");
s_match("something random", "Rand");
return 0;
}
- Output:
matching `A Short String' with `ort S': matched: pos 4 end match matching `aBaBaBaBa' with `aBa': matched: pos 0 matched: pos 2 matched: pos 4 matched: pos 6 (at end) matching `something random' with `Rand': end match
C#
class Program
{
public static void Main (string[] args)
{
var value = "abcd".StartsWith("ab");
value = "abcd".EndsWith("zn"); //returns false
value = "abab".Contains("bb"); //returns false
value = "abab".Contains("ab"); //returns true
int loc = "abab".IndexOf("bb"); //returns -1
loc = "abab".IndexOf("ab"); //returns 0
loc = "abab".IndexOf("ab",loc+1); //returns 2
}
}
C++
#include <string>
using namespace std;
string s1="abcd";
string s2="abab";
string s3="ab";
//Beginning
s1.compare(0,s3.size(),s3)==0;
//End
s1.compare(s1.size()-s3.size(),s3.size(),s3)==0;
//Anywhere
s1.find(s2)//returns string::npos
int loc=s2.find(s3)//returns 0
loc=s2.find(s3,loc+1)//returns 2
Clojure
(def evals '((. "abcd" startsWith "ab")
(. "abcd" endsWith "zn")
(. "abab" contains "bb")
(. "abab" contains "ab")
(. "abab" indexOf "bb")
(let [loc (. "abab" indexOf "ab")]
(. "abab" indexOf "ab" (dec loc)))))
user> (for [i evals] [i (eval i)])
([(. "abcd" startsWith "ab") true] [(. "abcd" endsWith "zn") false] [(. "abab" contains "bb") false] [(. "abab" contains "ab") true] [(. "abab" indexOf "bb") -1] [(let [loc (. "abab" indexOf "ab")] (. "abab" indexOf "ab" (dec loc))) 0])
CoffeeScript
This example uses string slices, but a better implementation might use indexOf for slightly better performance.
matchAt = (s, frag, i) ->
s[i...i+frag.length] == frag
startsWith = (s, frag) ->
matchAt s, frag, 0
endsWith = (s, frag) ->
matchAt s, frag, s.length - frag.length
matchLocations = (s, frag) ->
(i for i in [0..s.length - frag.length] when matchAt s, frag, i)
console.log startsWith "tacoloco", "taco" # true
console.log startsWith "taco", "tacoloco" # false
console.log startsWith "tacoloco", "talk" # false
console.log endsWith "tacoloco", "loco" # true
console.log endsWith "loco", "tacoloco" # false
console.log endsWith "tacoloco", "yoco" # false
console.log matchLocations "bababab", "bab" # [0,2,4]
console.log matchLocations "xxx", "x" # [0,1,2]
Common Lisp
(defun starts-with-p (str1 str2)
"Determine whether `str1` starts with `str2`"
(let ((p (search str2 str1)))
(and p (= 0 p))))
(print (starts-with-p "foobar" "foo")) ; T
(print (starts-with-p "foobar" "bar")) ; NIL
(defun ends-with-p (str1 str2)
"Determine whether `str1` ends with `str2`"
(let ((p (mismatch str2 str1 :from-end T)))
(or (not p) (= 0 p))))
(print (ends-with-p "foobar" "foo")) ; NIL
(print (ends-with-p "foobar" "bar")) ; T
(defun containsp (str1 str2)
"Determine whether `str1` contains `str2`.
Instead of just returning T, return a list of starting locations
for every occurence of `str2` in `str1`"
(unless (string-equal str2 "")
(loop for p = (search str2 str1) then (search str2 str1 :start2 (1+ p))
while p
collect p)))
(print (containsp "foobar" "oba")) ; (2)
(print (containsp "ababaBa" "ba")) ; (1 3)
(print (containsp "foobar" "x")) ; NIL
Component Pascal
BlackBox Component Builder
MODULE StringMatch;
IMPORT StdLog,Strings;
CONST
strSize = 1024;
patSize = 256;
TYPE
Matcher* = POINTER TO LIMITED RECORD
str: ARRAY strSize OF CHAR;
pat: ARRAY patSize OF CHAR;
pos: INTEGER
END;
PROCEDURE NewMatcher*(IN str: ARRAY OF CHAR): Matcher;
VAR
m: Matcher;
BEGIN
NEW(m);m.str := str$;m.pos:= 0;
RETURN m
END NewMatcher;
PROCEDURE (m: Matcher) Match*(IN pat: ARRAY OF CHAR): INTEGER,NEW;
VAR
pos: INTEGER;
BEGIN
m.pat := pat$;
pos := m.pos;
Strings.Find(m.str,m.pat,pos,m.pos);
RETURN m.pos
END Match;
PROCEDURE (m: Matcher) Next*(): INTEGER, NEW;
VAR
pos: INTEGER;
BEGIN
pos := m.pos + LEN(m.pat$);
Strings.Find(m.str,m.pat,pos,m.pos);
RETURN m.pos;
END Next;
(* Some Helper functions based on Strings module *)
PROCEDURE StartsWith(IN str: ARRAY OF CHAR;IN pat: ARRAY OF CHAR): BOOLEAN;
VAR
pos: INTEGER;
BEGIN
Strings.Find(str,pat,0,pos);
RETURN pos = 0
END StartsWith;
PROCEDURE Contains(IN str: ARRAY OF CHAR;IN pat: ARRAY OF CHAR; OUT pos: INTEGER): BOOLEAN;
BEGIN
Strings.Find(str,pat,0,pos);
RETURN pos >= 0
END Contains;
PROCEDURE EndsWith(IN str: ARRAY OF CHAR;IN pat: ARRAY OF CHAR): BOOLEAN;
VAR
pos: INTEGER;
BEGIN
Strings.Find(str,pat,0,pos);
RETURN pos + LEN(pat$) = LEN(str$)
END EndsWith;
PROCEDURE Do*;
CONST
aStr = "abcdefghijklmnopqrstuvwxyz";
VAR
pat: ARRAY 128 OF CHAR;
res: BOOLEAN;
at: INTEGER;
m: Matcher;
BEGIN
(* StartsWith *)
pat := "abc";
StdLog.String(aStr + " startsWith " + pat + " :>");StdLog.Bool(StartsWith(aStr,pat));StdLog.Ln;
pat := "cba";
StdLog.String(aStr + " startsWith " + pat + " :>");StdLog.Bool(StartsWith(aStr,pat));StdLog.Ln;
pat := "def";
StdLog.String(aStr + " startsWith " + pat + " :>");StdLog.Bool(StartsWith(aStr,pat));StdLog.Ln;
StdLog.Ln;
(* Contains *)
pat := 'def';
StdLog.String(aStr + " contains " + pat + " :>");StdLog.Bool(Contains(aStr,pat,at));
StdLog.String(" at: ");StdLog.Int(at);StdLog.Ln;
pat := 'efd';
StdLog.String(aStr + " contains " + pat + " :>");StdLog.Bool(Contains(aStr,pat,at));
StdLog.String(" at: ");StdLog.Int(at);StdLog.Ln;
pat := 'abc';
StdLog.String(aStr + " contains " + pat + " :>");StdLog.Bool(Contains(aStr,pat,at));
StdLog.String(" at: ");StdLog.Int(at);StdLog.Ln;
pat := 'xyz';
StdLog.String(aStr + " contains " + pat + " :>");StdLog.Bool(Contains(aStr,pat,at));
StdLog.String(" at: ");StdLog.Int(at);StdLog.Ln;
StdLog.Ln;
(* EndsWith *)
pat := 'xyz';
StdLog.String(aStr + " endsWith " + pat + " :>");StdLog.Bool(EndsWith(aStr,pat));StdLog.Ln;
pat := 'zyx';
StdLog.String(aStr + " endsWith " + pat + " :>");StdLog.Bool(EndsWith(aStr,pat));StdLog.Ln;
pat := 'abc';
StdLog.String(aStr + " endsWith " + pat + " :>");StdLog.Bool(EndsWith(aStr,pat));StdLog.Ln;
pat:= 'def';
StdLog.String(aStr + " endsWith " + pat + " :>");StdLog.Bool(EndsWith(aStr,pat));StdLog.Ln;
StdLog.Ln;
m := NewMatcher("abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz");
StdLog.String("Matching 'abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz' against 'abc':> ");
StdLog.Ln;
StdLog.String("Match at: ");StdLog.Int(m.Match("abc"));StdLog.Ln;
StdLog.String("Match at: ");StdLog.Int(m.Next());StdLog.Ln;
StdLog.String("Match at: ");StdLog.Int(m.Next());StdLog.Ln
END Do;
END StringMatch.
Execute: ^Q StringMatching.Do
- Output:
abcdefghijklmnopqrstuvwxyz startsWith abc :> $TRUE abcdefghijklmnopqrstuvwxyz startsWith cba :> $FALSE abcdefghijklmnopqrstuvwxyz startsWith def :> $FALSE abcdefghijklmnopqrstuvwxyz contains def :> $TRUE at: 3 abcdefghijklmnopqrstuvwxyz contains efd :> $FALSE at: -1 abcdefghijklmnopqrstuvwxyz contains abc :> $TRUE at: 0 abcdefghijklmnopqrstuvwxyz contains xyz :> $TRUE at: 23 abcdefghijklmnopqrstuvwxyz endsWith xyz :> $TRUE abcdefghijklmnopqrstuvwxyz endsWith zyx :> $FALSE abcdefghijklmnopqrstuvwxyz endsWith abc :> $FALSE abcdefghijklmnopqrstuvwxyz endsWith def :> $FALSE Matching 'abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz' against 'abc':> Match at: 0 Match at: 26 Match at: -1
D
void main() {
import std.stdio;
import std.algorithm: startsWith, endsWith, find, countUntil;
"abcd".startsWith("ab").writeln; // true
"abcd".endsWith("zn").writeln; // false
"abab".find("bb").writeln; // empty array (no match)
"abcd".find("bc").writeln; // "bcd" (substring start
// at match)
"abab".countUntil("bb").writeln; // -1 (no match)
"abab".countUntil("ba").writeln; // 1 (index of 1st match)
// std.algorithm.startsWith also works on arrays and ranges:
[1, 2, 3].countUntil(3).writeln; // 2
[1, 2, 3].countUntil([2, 3]).writeln; // 1
}
- Output:
true false bcd -1 1 2 1
DCL
$ first_string = p1
$ length_of_first_string = f$length( first_string )
$ second_string = p2
$ length_of_second_string = f$length( second_string )
$ offset = f$locate( second_string, first_string )
$ if offset .eq. 0
$ then
$ write sys$output "first string starts with second string"
$ else
$ write sys$output "first string does not start with second string"
$ endif
$ if offset .ne. length_of_first_string
$ then
$ write sys$output "first string contains the second string at location ", offset
$ else
$ write sys$output "first string does not contain the second string at any location"
$ endif
$ temp = f$extract( length_of_first_string - length_of_second_string, length_of_second_string, first_string )
$ if second_string .eqs. temp
$ then
$ write sys$output "first string ends with the second string"
$ else
$ write sys$output "first string does not end with the second string"
$ endif
- Output:
$ @string_matching efabcdef ef first string starts with second string first string contains the second string at location 0 first string ends with the second string $ @string_matching efabcdef ab first string does not start with second string first string contains the second string at location 2 first string does not end with the second string $ @string_matching efabcdef def first string does not start with second string first string contains the second string at location 5 first string ends with the second string $ @string_matching efabcdef defx first string does not start with second string first string does not contain the second string at any location first string does not end with the second string
Delphi
program CharacterMatching;
{$APPTYPE CONSOLE}
uses StrUtils;
begin
WriteLn(AnsiStartsText('ab', 'abcd')); // True
WriteLn(AnsiEndsText('zn', 'abcd')); // False
WriteLn(AnsiContainsText('abcd', 'bb')); // False
Writeln(AnsiContainsText('abcd', 'ab')); // True
WriteLn(Pos('ab', 'abcd')); // 1
end.
DuckDB
In the following typescript, "D " signifies the DuckDB prompt.
D .mode list
D .header off
# starts_with/2 is boolean:
D select starts_with('abc','ab');
true
# Equivalently:
D select ('abc').starts_with('ab');
true
# Syntax: position(<needle> in <haystack>)
D select position('bc' in 'abcd');
2
# ends_with/2 is also boolean but might have been renamed suffix()
D select ('abc').suffix('bc');
true
# regexp_matches() can also be used, e.g.
D select ('abc').regexp_matches('^ab');
true
All indices
Here's a function for finding all occurrences of one string in another:
# Return a list of the indices of all occurrences (including overlapping occurrences)
create or replace function string_positions(haystack, needle) as (
WITH RECURSIVE etc AS (
SELECT
position(needle IN haystack) AS start_pos,
0 as s
UNION ALL
SELECT
position(needle IN substr(haystack, start_pos + 1)) + start_pos AS start_pos,
start_pos as s
FROM etc
WHERE start_pos != s
)
SELECT coalesce(array_agg(start_pos order by start_pos),[]::BIGINT[])
FROM etc
WHERE start_pos > 0 and s != start_pos
);
Dyalect
var value = "abcd".StartsWith("ab")
value = "abcd".EndsWith("zn") //returns false
value = "abab".Contains("bb") //returns false
value = "abab".Contains("ab") //returns true
var loc = "abab".IndexOf("bb") //returns -1
loc = "abab".IndexOf("ab") //returns 0E
def f(string1, string2) {
println(string1.startsWith(string2))
var index := 0
while ((index := string1.startOf(string2, index)) != -1) {
println(`at $index`)
index += 1
}
println(string1.endsWith(string2))
}EasyLang
func starts s$ t$ .
if substr s$ 1 len t$ = t$
return 1
.
return 0
.
func ends s$ t$ .
if substr s$ (len s$ - len t$ + 1) len t$ = t$
return 1
.
return 0
.
func contains s$ t$ .
return if strpos s$ t$ > 0
.
print starts "hello world" "he"
print ends "hello world" "rld"
print contains "hello world" "wor"
EchoLisp
(string-suffix? "nette" "Antoinette") → #t
(string-prefix? "Simon" "Simon & Garfunkel") → #t
(string-match "Antoinette" "net") → #t ;; contains
(string-index "net" "Antoinette") → 5 ;; substring location
ed
This script joins two strings (each on the line of its own) with vertical bar and then does regex matching against them.
H
s/^/|/
,j
t0
t0
1s/^(.*)(.*)\|\1$/String \1\2 starts with \1/
1s/^(.*)\|(.*)/String \1 does not start with \2/
2s/^(.*)(.*)(.*)\|\2$/String \1\2\3 contains \2/
2s/^(.*)\|(.*)/String \1 does not contain \2/
3s/^(.*)(.*)\|\2$/String \1\2 ends with \2/
3s/^(.*)\|(.*)/String \1 does not end with \2/
,p
Q
- Output:
$ cat string-matching.ed | ed -lEGs string-matching.input String abab starts with ab String abab contains ab String abab ends with ab
Elena
ELENA 6.x :
import extensions;
public program()
{
var s := "abcd";
console.printLine(s," starts with ab: ",s.startingWith("ab"));
console.printLine(s," starts with cd: ",s.startingWith("cd"));
console.printLine(s," ends with ab: ",s.endingWith("ab"));
console.printLine(s," ends with cd: ",s.endingWith("cd"));
console.printLine(s," contains ab: ",s.containing("ab"));
console.printLine(s," contains bc: ",s.containing("bc"));
console.printLine(s," contains cd: ",s.containing("cd"));
console.printLine(s," contains az: ",s.containing("az"));
console.printLine(s," index of az: ",s.indexOf(0, "az"));
console.printLine(s," index of cd: ",s.indexOf(0, "cd"));
console.printLine(s," index of bc: ",s.indexOf(0, "bc"));
console.printLine(s," index of ab: ",s.indexOf(0, "ab"));
console.readChar()
}Elixir
The String module has functions that cover the base requirements.
s1 = "abcd"
s2 = "adab"
s3 = "ab"
String.starts_with?(s1, s3)
# => true
String.starts_with?(s2, s3)
# => false
String.contains?(s1, s3)
# => true
String.contains?(s2, s3)
# => true
String.ends_with?(s1, s3)
# => false
String.ends_with?(s2, s3)
# => true
# Optional requirements:
Regex.run(~r/#{s3}/, s1, return: :index)
# => [{0, 2}]
Regex.run(~r/#{s3}/, s2, return: :index)
# => [{2, 2}]
Regex.scan(~r/#{s3}/, "abcabc", return: :index)
# => [[{0, 2}], [{3, 2}]]
Emacs Lisp
(defun string-contains (needle haystack)
(string-match (regexp-quote needle) haystack))
(string-prefix-p "before" "before center after") ;=> t
(string-contains "before" "before center after") ;=> 0
(string-suffix-p "before" "before center after") ;=> nil
(string-prefix-p "center" "before center after") ;=> nil
(string-contains "center" "before center after") ;=> 7
(string-suffix-p "center" "before center after") ;=> nil
(string-prefix-p "after" "before center after") ;=> nil
(string-contains "after" "before center after") ;=> 14
(string-suffix-p "after" "before center after") ;=> t
Erlang
-module(character_matching).
-export([starts_with/2,ends_with/2,contains/2]).
%% Both starts_with and ends_with are mappings to 'lists:prefix/2' and
%% 'lists:suffix/2', respectively.
starts_with(S1,S2) ->
lists:prefix(S2,S1).
ends_with(S1,S2) ->
lists:suffix(S2,S1).
contains(S1,S2) ->
contains(S1,S2,1,[]).
%% While S1 is at least as long as S2 we check if S2 is its prefix,
%% storing the result if it is. When S1 is shorter than S2, we return
%% the result. NB: this will work on any arbitrary list in erlang
%% since it makes no distinction between strings and lists.
contains([_|T]=S1,S2,N,Acc) when length(S2) =< length(S1) ->
case starts_with(S1,S2) of
true ->
contains(T,S2,N+1,[N|Acc]);
false ->
contains(T,S2,N+1,Acc)
end;
contains(_S1,_S2,_N,Acc) ->
Acc.
Euphoria
sequence first, second
integer x
first = "qwertyuiop"
-- Determining if the first string starts with second string
second = "qwerty"
if match(second, first) = 1 then
printf(1, "'%s' starts with '%s'\n", {first, second})
else
printf(1, "'%s' does not start with '%s'\n", {first, second})
end if
-- Determining if the first string contains the second string at any location
-- Print the location of the match for part 2
second = "wert"
x = match(second, first)
if x then
printf(1, "'%s' contains '%s' at position %d\n", {first, second, x})
else
printf(1, "'%s' does not contain '%s'\n", {first, second})
end if
-- Determining if the first string ends with the second string
second = "uio"
if length(second)<=length(first) and match_from(second, first, length(first)-length(second)+1) then
printf(1, "'%s' ends with '%s'\n", {first, second})
else
printf(1, "'%s' does not end with '%s'\n", {first, second})
end if- Output:
'qwertyuiop' starts with 'qwerty' 'qwertyuiop' contains 'wert' at position 2 'qwertyuiop' does not end with 'uio'
F#
[<EntryPoint>]
let main args =
let text = "一二三四五六七八九十"
let starts = "一二"
let ends = "九十"
let contains = "五六"
let notContains = "百"
printfn "text = %A" text
printfn "starts with %A: %A" starts (text.StartsWith(starts))
printfn "starts with %A: %A" ends (text.StartsWith(ends))
printfn "ends with %A: %A" ends (text.EndsWith(ends))
printfn "ends with %A: %A" starts (text.EndsWith(starts))
printfn "contains %A: %A" contains (text.Contains(contains))
printfn "contains %A: %A" notContains (text.Contains(notContains))
printfn "substring %A begins at position %d (zero-based)" contains (text.IndexOf(contains))
let text2 = text + text
printfn "text = %A" text2
Seq.unfold (fun (n : int) ->
let idx = text2.IndexOf(contains, n)
if idx < 0 then None else Some (idx, idx+1)) 0
|> Seq.iter (printfn "substring %A begins at position %d (zero-based)" contains)
0
- Output:
text = "一二三四五六七八九十" starts with "一二": true starts with "九十": false ends with "九十": true ends with "一二": false contains "五六": true contains "百": false substring "五六" begins at position 4 (zero-based) text = "一二三四五六七八九十一二三四五六七八九十" substring "五六" begins at position 4 (zero-based) substring "五六" begins at position 14 (zero-based)
Factor
Does cheesecake start with cheese?
"cheesecake" "cheese" head? ! t
Does cheesecake contain sec at any location?
"sec" "cheesecake" subseq? ! t
Does cheesecake end with cake?
"cheesecake" "cake" tail? ! t
Where in cheesecake is the leftmost sec?
"sec" "cheesecake" subseq-start ! 4
Where in Mississippi are all occurrences of iss?
USE: regexp
"Mississippi" "iss" <regexp> all-matching-slices [ from>> ] map ! { 1 4 }
Falcon
'VBA/Python programmer's approach. I'm just a junior Falconeer but this code seems falconic
/* created by Aykayayciti Earl Lamont Montgomery
April 9th, 2018 */
s1 = "Naig Ialocin Olracnaig"
s2 = "Naig"
var = s1.startsWith(s2) ? s1 + " starts with " + s2 : s1 + " does not start with " + s2
> var
s2 = "loc"
var = s2 in s1 ? @ "$s1 contains $s2" : @ "$s1 does not contain $s2"
> var
> s1.endsWith(s2) ? @ "s1 ends with $s2" : @ "$s1 does not end with $s2"- Output:
Naig Ialocin Olracnaig starts with Naig Naig Ialocin Olracnaig contains loc Naig Ialocin Olracnaig does not end with loc [Finished in 1.2s]
Fantom
Fantom provides several self-explanatory string-matching methods:
startsWithendsWithcontainsindex(takes an optional index, for the start position)indexIgnoreCase(like above, ignoring case for ASCII characters)indexr(start search from end of string, with an optional index)indexrIgnoreCase(like above, ignoring case for ASCII characters)
class Main
{
public static Void main ()
{
string := "Fantom Language"
echo ("String is: " + string)
echo ("does string start with 'Fantom'? " + string.startsWith("Fantom"))
echo ("does string start with 'Language'? " + string.startsWith("Language"))
echo ("does string contain 'age'? " + string.contains("age"))
echo ("does string contain 'page'? " + string.contains("page"))
echo ("does string end with 'Fantom'? " + string.endsWith("Fantom"))
echo ("does string end with 'Language'? " + string.endsWith("Language"))
echo ("Location of 'age' is: " + string.index("age"))
posn := string.index ("an")
echo ("First location of 'an' is: " + posn)
posn = string.index ("an", posn+1)
echo ("Second location of 'an' is: " + posn)
posn = string.index ("an", posn+1)
if (posn == null) echo ("No third location of 'an'")
}
}- Output:
String is: Fantom Language does string start with 'Fantom'? true does string start with 'Language'? false does string contain 'age'? true does string contain 'page'? false does string end with 'Fantom'? false does string end with 'Language'? true Location of 'age' is: 12 First location of 'an' is: 1 Second location of 'an' is: 8 No third location of 'an'
FBSL
#APPTYPE CONSOLE
DIM s = "roko, mat jane do"
IF LEFT(s, 4) = "roko" THEN PRINT STRENC(s), " starts with ", STRENC("roko")
IF INSTR(s, "mat") THEN PRINT STRENC(s), " contains ", STRENC("mat"), " at ", INSTR
IF RIGHT(s, 2) = "do" THEN PRINT STRENC(s), " ends with ", STRENC("do")
PRINT STRENC(s), " contains ", STRENC("o"), " at the following locations:", InstrEx(s, "o")
PAUSE
SUB InstrEx(mane, match)
INSTR = 0
WHILE INSTR(mane, match, INSTR + 1): PRINT " ", INSTR;: WEND
END SUB
- Output:
"roko, mat jane do" starts with "roko" "roko, mat jane do" contains "mat" at 7 "roko, mat jane do" ends with "do" "roko, mat jane do" contains "o" at the following locations: 2 4 17 Press any key to continue...
Forth
: starts-with ( a l a2 l2 -- ? )
tuck 2>r min 2r> compare 0= ;
: ends-with ( a l a2 l2 -- ? )
tuck 2>r negate over + 0 max /string 2r> compare 0= ;
\ use SEARCH ( a l a2 l2 -- a3 l3 ? ) for contains
Fortran
Fortran does not offer a string type, but since F77 it has been possible to use a CHARACTER variable, of some specified size, whose size may be accessed via the LEN function. When passed as a parameter, a secret additional parameter specifies its size and so string-like usage is possible. Character matching is case sensitive, and, trailing spaces are ignored so that "xx" and "xx " are deemed equal. The function INDEX(text,target) determines the first index in text where target matches, and returns zero if there is no such match. Unfortunately, the function does not allow the specification of a starting position for a search, as to find any second and further matches. One must specify something like INDEX(text(5:),target) to start with position five, and then deal with the resulting offsets needed to relate the result to positions within the parameter. On the other hand, since there is no "length" conjoined to the text such substring selections can be made without copying the text to a work area, unlike the copy(text,start,stop) equivalent of Pascal for example. Some Fortran compilers do offer a starting point, and also an option to search backwards from the end, but these facilities are not guaranteed. Similarly, INDEX is only made available for CHARACTER searching, even though it could easily be generalised to other types.
A second problem is presented by the possibility that a logical expression such as L.LT.0 .OR. etc. will always or might possibly or in certain constructions but not others be fully evaluated, which is to say that the etc will be evaluated even though L < 0 is true so that the result is determined. And in this case, evaluating the etc will cause trouble because the indexing won't work! To be safe, therefore, a rather lame two-stage test is required - though optimising compilers might well shift code around anyway.
In the case of STARTS, these annoyances can be left to the INDEX function rather than comparing the start of A against B. At the cost of it searching the whole of A if B is not at the start. Otherwise, it would be the mirror of ENDS.
SUBROUTINE STARTS(A,B) !Text A starts with text B?
CHARACTER*(*) A,B
IF (INDEX(A,B).EQ.1) THEN !Searches A to find B.
WRITE (6,*) ">",A,"< starts with >",B,"<"
ELSE
WRITE (6,*) ">",A,"< does not start with >",B,"<"
END IF
END SUBROUTINE STARTS
SUBROUTINE HAS(A,B) !Text B appears somewhere in text A?
CHARACTER*(*) A,B
INTEGER L
L = INDEX(A,B) !The first position in A where B matches.
IF (L.LE.0) THEN
WRITE (6,*) ">",A,"< does not contain >",B,"<"
ELSE
WRITE (6,*) ">",A,"< contains a >",B,"<, offset",L
END IF
END SUBROUTINE HAS
SUBROUTINE ENDS(A,B) !Text A ends with text B.
CHARACTER*(*) A,B
INTEGER L
L = LEN(A) - LEN(B) !Find the tail end of A that B might match.
IF (L.LT.0) THEN !Dare not use an OR, because of full evaluation risks.
WRITE (6,*) ">",A,"< is too short to end with >",B,"<" !Might as well have a special message.
ELSE IF (A(L + 1:L + LEN(B)).NE.B) THEN !Otherwise, it is safe to look.
WRITE (6,*) ">",A,"< does not end with >",B,"<"
ELSE
WRITE (6,*) ">",A,"< ends with >",B,"<"
END IF
END SUBROUTINE ENDS
CALL STARTS("This","is")
CALL STARTS("Theory","The")
CALL HAS("Bananas","an")
CALL ENDS("Banana","an")
CALL ENDS("Banana","na")
CALL ENDS("Brief","Much longer")
END
Output: text strings are bounded by >etc.< in case of leading or trailing spaces.
>This< does not start with >is< >Theory< starts with >The< >Bananas< contains a >an<, offset 2 >Banana< does not end with >an< >Banana< ends with >na< >Brief< is too short to end with >Much longer<
Similar program using modern Fortran style
!-----------------------------------------------------------------------
!Main program string_matching
!-----------------------------------------------------------------------
program string_matching
implicit none
character(len=*), parameter :: fmt= '(I0)'
write(*,fmt) starts("this","is")
write(*,fmt) starts("theory","the")
write(*,fmt) has("bananas","an")
write(*,fmt) ends("banana","an")
write(*,fmt) ends("banana","na")
write(*,fmt) ends("brief","much longer")
contains
! Determining if the first string starts with second string
function starts(string1, string2) result(answer)
implicit none
character(len=*), intent(in) :: string1
character(len=*), intent(in) :: string2
integer :: answer
answer = 0
if(len(string2)>len(string1)) return
if(string1(1:len(string2))==string2) answer = 1
end function starts
! Determining if the first string contains the second string at any location
function has(string1, string2) result(answer)
implicit none
character(len=*), intent(in) :: string1
character(len=*), intent(in) :: string2
character(len=:),allocatable :: temp
integer :: answer, add
character(len=*), parameter :: fmt= '(A6,X,I0)'
answer = 0
add = 0
if(len(string2)>len(string1)) return
answer = index(string1, string2)
if(answer==0) return
! Print the location of the match for part 2
write(*,fmt) " at ", answer
! Handle multiple occurrences of a string for part 2.
add = answer
temp = string1(answer+1:)
do while(answer>0)
answer = index(temp, string2)
add = add + answer
if(answer>0) write(*,fmt) " at ", add
! deallocate(temp)
temp = string1(add+1:) ! auto reallocation
enddo
answer = 1
end function has
! Determining if the first string ends with the second string
function ends(string1, string2) result(answer)
implicit none
character(len=*), intent(in) :: string1
character(len=*), intent(in) :: string2
integer :: answer
answer = 0
if(len(string2)>len(string1)) return
if(string1(len(string1)-len(string2)+1:)==string2) answer = 1
end function ends
end program string_matching
Output: false = 0, true = 1 ( + multiple occurrences if applicable)
0 1 at 2 at 4 1 0 1 0
In recent standards of Fortran strings as intrinsic first-class type and many intrinsic procedures for strings manipulation have been added.
FreeBASIC
' FB 1.05.0 Win64
Dim As String s1 = "abracadabra"
Dim As String s2 = "abra"
Print "First string : "; s1
Print "Second string : "; s2
Print
Print "First string begins with second string : "; CBool(s2 = Left(s1, Len(s2)))
Dim As Integer i1 = Instr(s1, s2)
Dim As Integer i2
Print "First string contains second string : ";
If i1 Then
Print "at index"; i1;
i2 = Instr(i1 + Len(s2), s1, s2)
If i2 Then
Print " and at index"; i2
Else
Print
End If
Else
Print "false";
End If
Print "First string ends with second string : "; CBool(s2 = Right(s1, Len(s2)))
Print
Print "Press any key to quit"
Sleep
- Output:
First string : abracadabra Second string : abra First string begins with second string : true First string contains second string : at index 1 and at index 8 First string ends with second string : true
FutureBasic
window 1, @"String matching", (0,0,650,360)
void local fn DoIt
CFStringRef s1, s2
CFRange range
s1 = @"alphabravocharlie"
s2 = @"alpha"
if ( fn StringHasPrefix( s1, s2 ) )
print @"\"";s1;@"\" starts with \"";s2;@"\""
else
print @"\"";s1;@"\" does not start with \"";s2;@"\""
end if
print
s2 = @"bravo"
if ( fn StringHasPrefix( s1, s2 ) )
print @"\"";s1;@"\" starts with \"";s2;@"\""
else
print @"\"";s1;@"\" does not start with \"";s2;@"\""
end if
print
range = fn StringRangeOfString( s1, s2 )
if ( range.location != NSNotFound )
print @"\"";s1;@"\" contains \"";s2;@"\" at location ";(range.location)
else
print @"\"";s1;@"\" does not contain \"";s2;@"\""
end if
print
s2 = @"delta"
range = fn StringRangeOfString( s1, s2 )
if ( range.location != NSNotFound )
print @"\"";s1;@"\" contains \"";s2;@"\" at location ";(range.location)
else
print @"\"";s1;@"\" does not contain \"";s2;@"\""
end if
print
s2 = @"charlie"
if ( fn StringHasSuffix( s1, s2 ) )
print @"\"";s1;@"\" ends with \"";s2;@"\""
else
print @"\"";s1;@"\" does not end with \"";s2;@"\""
end if
print
s2 = @"alpha"
if ( fn StringHasSuffix( s1, s2 ) )
print @"\"";s1;@"\" ends with \"";s2;@"\""
else
print @"\"";s1;@"\" does not end with \"";s2;@"\""
end if
print
s1 = @"alpha delta charlie delta echo delta futurebasic"
s2 = @"delta"
range = fn StringRangeOfString( s1, s2 )
while ( range.location != NSNotFound )
print @"\"";s1;@"\" contains \"";s2;@"\" at location ";(range.location)
range.location++
range = fn StringRangeOfStringWithOptionsInRange( s1, s2, 0, fn CFRangeMake( range.location, len(s1)-range.location ) )
wend
end fn
fn DoIt
HandleEvents- Output:
"alphabravocharlie" starts with "alpha" "alphabravocharlie" does not start with "bravo" "alphabravocharlie" contains "bravo" at location 5 "alphabravocharlie" does not contain "delta" "alphabravocharlie" ends with "charlie" "alphabravocharlie" does not end with "alpha" "alpha delta charlie delta echo delta futurebasic" contains "delta" at location 6 "alpha delta charlie delta echo delta futurebasic" contains "delta" at location 20 "alpha delta charlie delta echo delta futurebasic" contains "delta" at location 31
Gambas
Click this link to run this code
Public Sub Main()
Dim sString1 As String = "Hello world"
Dim sString2 As String = "Hello"
Print sString1 Begins Left(sString2, 5) 'Determine if the first string starts with second string
If InStr(sString1, sString2) Then Print "True" Else Print "False" 'Determine if the first string contains the second string at any location
Print sString1 Ends Left(sString2, 5) 'Determine if the first string ends with the second string
End
Output:
True True False
GDScript
@tool
extends Node
@export var first_string: String
@export var second_string: String
@export var starts_with: bool:
get: return first_string.begins_with(second_string)
@export var contains: bool:
get: return first_string.contains(second_string)
@export var ends_with: bool:
get: return first_string.ends_with(second_string)
GML
#define charMatch
{
first = "qwertyuiop";
// Determining if the first string starts with second string
second = "qwerty";
if (string_pos(second, first) > 0) {
show_message("'" + first + "' starts with '" + second + "'");
} else {
show_message("'" + first + "' does not start with '" + second + "'");
}
second = "wert"
// Determining if the first string contains the second string at any location
// Print the location of the match for part 2
if (string_pos(second, first) > 0) {
show_message("'" + first + "' contains '" + second + "' at position " + string(x));
} else {
show_message("'" + first + "' does not contain '" + second + "'");
}
// Handle multiple occurrences of a string for part 2.
x = string_count(second, first);
show_message("'" + first + "' contains " + string(x) + " instances of '" + second + "'");
// Determining if the first string ends with the second string
second = "random garbage"
temp = string_copy(first,
(string_length(first) - string_length(second)) + 1,
string_length(second));
if (temp == second) {
show_message("'" + first + "' ends with '" + second + "'");
} else {
show_message("'" + first + "' does not end with '" + second + "'");
}
}- Output:
(in message boxes, 1 per line)
'qwertyuiop' starts with 'qwerty' 'qwertyuiop' contains 'wert' at position 0 'qwertyuiop' contains 1 instances of 'wert' 'qwertyuiop' does not end with 'random garbage'
Go
package main
import (
"fmt"
"strings"
)
func match(first, second string) {
fmt.Printf("1. %s starts with %s: %t\n",
first, second, strings.HasPrefix(first, second))
i := strings.Index(first, second)
fmt.Printf("2. %s contains %s: %t,\n", first, second, i >= 0)
if i >= 0 {
fmt.Printf("2.1. at location %d,\n", i)
for start := i+1;; {
if i = strings.Index(first[start:], second); i < 0 {
break
}
fmt.Printf("2.2. at location %d,\n", start+i)
start += i+1
}
fmt.Println("2.2. and that's all")
}
fmt.Printf("3. %s ends with %s: %t\n",
first, second, strings.HasSuffix(first, second))
}
func main() {
match("abracadabra", "abr")
}
- Output:
1. abracadabra starts with abr: true 2. abracadabra contains abr: true, 2.1. at location 0, 2.2. at location 7, 2.2. and that's all 3. abracadabra ends with abr: false
Groovy
Examples:
assert "abcd".startsWith("ab")
assert ! "abcd".startsWith("zn")
assert "abcd".endsWith("cd")
assert ! "abcd".endsWith("zn")
assert "abab".contains("ba")
assert ! "abab".contains("bb")
assert "abab".indexOf("bb") == -1 // not found flag
assert "abab".indexOf("ab") == 0
def indicesOf = { string, substring ->
if (!string) { return [] }
def indices = [-1]
while (true) {
indices << string.indexOf(substring, indices.last()+1)
if (indices.last() == -1) break
}
indices[1..<(indices.size()-1)]
}
assert indicesOf("abab", "ab") == [0, 2]
assert indicesOf("abab", "ba") == [1]
assert indicesOf("abab", "xy") == []
All assertions pass, so there is no output.
Haskell
> import Data.List
> "abc" `isPrefixOf` "abcdefg"
True
> "efg" `isSuffixOf` "abcdefg"
True
> "bcd" `isInfixOf` "abcdefg"
True
> "abc" `isInfixOf` "abcdefg" -- Prefixes and suffixes are also infixes
True
> let infixes a b = findIndices (isPrefixOf a) $ tails b
> infixes "ab" "abcdefabqqab"
[0,6,10]
Icon and Unicon
- Output:
Matching s2 :="ab" within s1:= "abcdabab" Test #1 beginning matches Test #2 all matches at positions [ 1 5 7 ] Test #3 ending matches
J
startswith=: ] -: ({.~ #)
contains=: +./@:E.~
endswith=: ] -: ({.~ -@#)
Example use:
'abcd' startswith 'ab'
1
'abcd' startswith 'cd'
0
'abcd' endswith 'ab'
0
'abcd' endswith 'cd'
1
'abcd' contains 'bb'
0
'abcd' contains 'ab'
1
'abcd' contains 'bc'
1
'abab' contains 'ab'
1
'abab' I.@E.~ 'ab' NB. find starting indicies
0 2
Note that these verbs contain no constraints restricting them to sequences of characters and so also apply to arrays of type other than character:
0 1 2 3 startswith 0 1 NB. integer
1
4.2 5.1 1.3 9 3 contains 1.3 4.2 NB. floating point
0
4.2 5.1 1.3 4.2 9 3 contains 1.3 4.2
1
Java
For this task consider the following strings
String string = "string matching";
String suffix = "ing";
The most idiomatic way of determining if a string starts with another string is to use the String.startsWith method.
string.startsWith(suffix)
Another way is to use a combination of String.substring and String.equals
string.substring(0, suffix.length()).equals(suffix)
To determine if a string contains at least one occurrence of another string, use the String.contains method.
string.contains(suffix)
A slightly more idiomatic approach would be to use the String.indexOf method, which will also return the index of the first character.
string.indexOf(suffix) != -1
The most idiomatic way of determining whether a string ends with another string is to use the String.endsWith method.
string.endsWith(suffix);
Similarly, a combination of String.substring and String.equals can be used.
string.substring(string.length() - suffix.length()).equals(suffix)
If you're looking to find the index of each occurrence, you can use the following.
int indexOf;
int offset = 0;
while ((indexOf = string.indexOf(suffix, offset)) != -1) {
System.out.printf("'%s' @ %d to %d%n", suffix, indexOf, indexOf + suffix.length() - 1);
offset = indexOf + 1;
}
'ing' @ 3 to 5 'ing' @ 12 to 14
Alternately
"abcd".startsWith("ab") //returns true
"abcd".endsWith("zn") //returns false
"abab".contains("bb") //returns false
"abab".contains("ab") //returns true
int loc = "abab".indexOf("bb") //returns -1
loc = "abab".indexOf("ab") //returns 0
loc = "abab".indexOf("ab",loc+1) //returns 2
public class JavaApplication6 {
public static void main(String[] args) {
String strOne = "complexity";
String strTwo = "udacity";
stringMatch(strOne, strTwo);
}
public static void stringMatch(String one, String two) {
boolean match = false;
if (one.charAt(0) == two.charAt(0)) {
System.out.println(match = true); // returns true
} else {
System.out.println(match); // returns false
}
for (int i = 0; i < two.length(); i++) {
int temp = i;
for (int x = 0; x < one.length(); x++) {
if (two.charAt(temp) == one.charAt(x)) {
System.out.println(match = true); //returns true
i = two.length();
}
}
}
int num1 = one.length() - 1;
int num2 = two.length() - 1;
if (one.charAt(num1) == two.charAt(num2)) {
System.out.println(match = true);
} else {
System.out.println(match = false);
}
}
}
JavaScript
var stringA = "tacoloco"
, stringB = "co"
, q1, q2, q2multi, m
, q2matches = []
// stringA starts with stringB
q1 = stringA.substring(0, stringB.length) == stringB
// stringA contains stringB
q2 = stringA.indexOf(stringB)
// multiple matches
q2multi = new RegExp(stringB,'g')
while(m = q2multi.exec(stringA)){
q2matches.push(m.index)
}
// stringA ends with stringB
q3 = stringA.substr(-stringB.length) == stringB
console.log("1: Does '"+stringA+"' start with '"+stringB+"'? " + ( q1 ? "Yes." : "No."))
console.log("2: Is '"+stringB+"' contained in '"+stringA+"'? " + (~q2 ? "Yes, at index "+q2+"." : "No."))
if (~q2 && q2matches.length > 1){
console.log(" In fact, it happens "+q2matches.length+" times within '"+stringA+"', at index"+(q2matches.length > 1 ? "es" : "")+" "+q2matches.join(', ')+".")
}
console.log("3: Does '"+stringA+"' end with '"+stringB+"'? " + ( q3 ? "Yes." : "No."))
- Output:
1: Does 'tacoloco' start with 'co'? No. 2: Is 'co' contained in 'tacoloco'? Yes, at index 2. In fact, it happens 2 times within 'tacoloco', at indexes 2, 6. 3: Does 'tacoloco' end with 'co'? Yes.
jq
Using the builtins of jq 1.4 and later:
# startswith/1 is boolean:
"abc" | startswith("ab")
#=> true# index/1 returns the index or null,
# so the jq test "if index(_) then ...." can be used
# without any type conversion.
"abcd" | index( "bc")
#=> 1# endswith/1 is also boolean:
"abc" | endswith("bc")
#=> trueUsing the regex functions available in jq 1.5:
"abc" | test( "^ab")
"abcd" | test("bc")
"abcd" | test("cd$")Multiple Occurrences
To determine all the indices of one string in another:
# In jq 1.4 or later:
jq -n '"abcdabcd" | indices("bc")'
[
1,
5
]
In jq 1.5, the regex function match/1 can also be used:
$ jq -n '"abcdabcd" | match("bc"; "g") | .offset'
1
5
Julia
startswith("abcd","ab") #returns true
findfirst("ab", "abcd") #returns 1:2, indices range where string was found
endswith("abcd","zn") #returns false
match(r"ab","abcd") != Nothing #returns true where 1st arg is regex string
for r in eachmatch(r"ab","abab")
println(r.offset)
end #returns 1, then 3 matching the two starting indices where the substring was found
K
startswith: {:[0<#p:_ss[x;y];~*p;0]}
endswith: {0=(-#y)+(#x)-*_ss[x;y]}
contains: {0<#_ss[x;y]}
Example:
startswith["abcd";"ab"]
1
startswith["abcd";"bc"]
0
endswith["abcd";"cd"]
1
endswith["abcd";"bc"]
0
contains["abcdef";"cde"]
1
contains["abcdef";"bdef"]
0
_ss["abcdabceabc";"abc"] / location of matches
0 4 8
Kotlin
fun main() {
val s1 = "abracadabra"
val s2 = "abra"
println("$s1 begins with $s2: ${s1.startsWith(s2)}")
println("$s1 ends with $s2: ${s1.endsWith(s2)}")
val b = s2 in s1
if (b) {
print("$s1 contains $s2 at these indices: ")
// can use indexOf to get first index or lastIndexOf to get last index
// to get ALL indices, use a for loop or Regex
println(
s2.toRegex(RegexOption.LITERAL).findAll(s1).joinToString { it.range.start.toString() }
)
}
else println("$s1 does not contain $2.")
}
- Output:
abracadabra begins with abra: true abracadabra ends with abra: true abracadabra contains abra at these indices: 0, 7
Ksh
#!/bin/ksh
exec 2> /tmp/String_matching.err
# String matching
# # 1. Determine if the first string starts with second string.
# # 2. Determine if the first string contains the second string at any location
# # 3. Determine if the first string ends with the second string
# # 4. Print the location of the match for part 2
# # 5. Handle multiple occurrences of a string for part 2
# # Variables:
#
typeset -a bounds=( [0]="no Match" [1]="Starts with" [255]="Ends with" )
typeset -a string=( "Hello" "hello world" "William Williams" "Yabba dabba do" )
typeset -a substr=( "Hell" "Do" "abba" "Will" "orld" )
# # Functions:
#
# # Function _bounds(str, substr) - return 1 for starts with 255 for endswith
#
function _bounds {
typeset _str ; _str="$1"
typeset _sub ; _sub="$2"
typeset _FALSE _STARTS _ENDS ; integer _FALSE=0 _STARTS=1 _ENDS=255
[[ "${_str}" == "${_sub}"* ]] && return ${_STARTS}
[[ "${_str}" == *"${_sub}" ]] && return ${_ENDS}
return ${_FALSE}
}
# # Function _contains(str, substr) - return 0 no match arr[pos1 ... posn]
#
function _contains {
typeset _str ; _str="$1"
typeset _sub ; _sub="$2"
typeset _arr ; nameref _arr="$3"
typeset _FALSE _TRUE _i _match _buff ; integer _FALSE=0 _TRUE=1 _i _match
[[ "${_str}" != *"${_sub}"* ]] && return ${_FALSE}
for ((_i=0; _i<=${#_str}-${#_sub}; _i++)); do
_buff=${_str:${_i}:$((${#_str}-_i))}
[[ ${_buff} != ${_buff#${_sub}} ]] && _arr+=( $(( _i+1 )) )
done
return ${_TRUE}
}
######
# main #
######
integer i j rc
typeset -a posarr
for ((i=0; i<${#string[*]}; i++)); do
for ((j=0; j<${#substr[*]}; j++)); do
_bounds "${string[i]}" "${substr[j]}" ; rc=$?
print "${string[i]} ${bounds[rc]} ${substr[j]}"
_contains "${string[i]}" "${substr[j]}" posarr ; rc=$?
((! rc)) && print "${string[i]} ${substr[j]} ${bounds[rc]}es" && continue
print "${string[i]} + ${substr[j]} ${#posarr[*]} matches at ${posarr[*]}"
unset posarr ; typeset -a posarr
done
done
- Output:
Hello Starts with Hell Hello + Hell 1 matches at 1 Hello no Match Do Hello Do no Matches Hello no Match abba Hello abba no Matches Hello no Match Will Hello Will no Matches Hello no Match orld Hello orld no Matches hello world no Match Hell hello world Hell no Matches hello world no Match Do hello world Do no Matches hello world no Match abba hello world abba no Matches hello world no Match Will hello world Will no Matches hello world Ends with orld hello world + orld 1 matches at 8 William Williams no Match Hell William Williams Hell no Matches William Williams no Match Do William Williams Do no Matches William Williams no Match abba William Williams abba no Matches William Williams Starts with Will William Williams + Will 2 matches at 1 9 William Williams no Match orld William Williams orld no Matches Yabba dabba do no Match Hell Yabba dabba do Hell no Matches Yabba dabba do no Match Do Yabba dabba do Do no Matches Yabba dabba do no Match abba Yabba dabba do + abba 2 matches at 2 8 Yabba dabba do no Match Will Yabba dabba do Will no Matches Yabba dabba do no Match orld
Yabba dabba do orld no Matches
LabVIEW
These images solve the task's requirements in order.
This image is a VI Snippet, an executable image of LabVIEW code. The LabVIEW version is shown on the top-right hand corner. You can download it, then drag-and-drop it onto the LabVIEW block diagram from a file browser, and it will appear as runnable, editable code.
Lambdatalk
{def S.in
{def S.in.r {lambda {:c :w :i :n}
{if {= :i :n}
then -1
else {if {W.equal? :c {W.get :i :w}}
then :i
else {S.in.r :c :w {+ :i 1} :n}}}}}
{lambda {:c :w}
{S.in.r :c :w 0 {W.length :w}}}}
-> S.in
{def startswith
{lambda {:w1 :w2}
{= {S.in _ {S.replace :w2 by _ in :w1}} 0}}}
-> startswith
{def endswith
{lambda {:w1 :w2}
{= {S.in _ {S.replace :w2 by _ in :w1}}
{- {W.length :w1} {W.length :w2}}}}}
-> endswith
{def isin
{lambda {:w1 :w2}
{S.in _ {S.replace :w2 by _ in :w1}}}}
-> isin
{startswith nabuchodonosor nabu}
-> true
{startswith nabuchodonosor abu}
-> false
{endswith nabuchodonosor sor}
-> true
{endswith nabuchodonosor oso}
-> false
{isin nabuchodonosor oso}
-> 10 // is in at 10
{isin nabuchodonosor xyz}
-> -1 // is not in
Lang5
: 2array 2 compress ; : bi* '_ set dip _ execute ; : bi@ dup bi* ;
: comb "" split ; : concat "" join ; : dip swap '_ set execute _ ;
: first 0 extract swap drop ; : flip comb reverse concat ;
: contains
swap 'comb bi@ length do # create a matrix.
1 - "dup 1 1 compress rotate" dip dup 0 == if break then
loop drop length compress swap drop
"length 1 -" bi@ rot 0 0 "'2array dip" '2array bi* swap 2array slice reverse
: concat.(*) concat ;
'concat "'concat. apply" bi* eq 1 1 compress index collapse
length if expand drop else drop 0 then ; # r: position.
: end-with 'flip bi@ start-with ;
: start-with 'comb bi@ length rot swap iota subscript 'concat bi@ eq ;
"rosettacode" "rosetta" start-with . # 1
"rosettacode" "taco" contains . # 5
"rosettacode" "ocat" contains . # 0
"rosettacode" "edoc" end-with . # 0
"rosettacode" "code" contains . # 7Lasso
local(
a = 'a quick brown peanut jumped over a quick brown fox',
b = 'a quick brown'
)
//Determining if the first string starts with second string
#a->beginswith(#b) // true
//Determining if the first string contains the second string at any location
#a >> #b // true
#a->contains(#b) // true
//Determining if the first string ends with the second string
#a->endswith(#b) // false
Liberty BASIC
'1---Determining if the first string starts with second string
st1$="first string"
st2$="first"
if left$(st1$,len(st2$))=st2$ then
print "First string starts with second string."
end if
'2---Determining if the first string contains the second string at any location
'2.1---Print the location of the match for part 2
st1$="Mississippi"
st2$="i"
if instr(st1$,st2$) then
print "First string contains second string."
print "Second string is at location ";instr(st1$,st2$)
end if
'2.2---Handle multiple occurrences of a string for part 2.
pos=instr(st1$,st2$)
while pos
count=count+1
pos=instr(st1$,st2$,pos+len(st2$))
wend
print "Number of times second string appears in first string is ";count
'3---Determining if the first string ends with the second string
st1$="first string"
st2$="string"
if right$(st1$,len(st2$))=st2$ then
print "First string ends with second string."
end ifLingo
a = "Hello world!"
b = "Hello"
-- Determining if the first string starts with second string
put a starts b
-- 1
-- Determining if the first string contains the second string at any location
put a contains b
-- 1
-- Determining if the first string ends with the second string
put a.char[a.length-b.length+1..a.length] = b
-- 0
b = "world!"
put a.char[a.length-b.length+1..a.length] = b
-- 1
-- Print the location of the match for part 2
put offset(b, a)
-- 7Logo
to starts.with? :sub :thing
if empty? :sub [output "true]
if empty? :thing [output "false]
if not equal? first :sub first :thing [output "false]
output starts.with? butfirst :sub butfirst :thing
end
to ends.with? :sub :thing
if empty? :sub [output "true]
if empty? :thing [output "false]
if not equal? last :sub last :thing [output "false]
output ends.with? butlast :sub butlast :thing
end
show starts.with? "dog "doghouse ; true
show ends.with? "house "doghouse ; true
show substring? "gho "doghouse ; true (built-in)Lua
s1 = "string"
s2 = "str"
s3 = "ing"
s4 = "xyz"
print( "s1 starts with s2: ", string.find( s1, s2 ) == 1 )
print( "s1 starts with s3: ", string.find( s1, s3 ) == 1, "\n" )
print( "s1 contains s3: ", string.find( s1, s3 ) ~= nil )
print( "s1 contains s3: ", string.find( s1, s4 ) ~= nil, "\n" )
print( "s1 ends with s2: ", select( 2, string.find( s1, s2 ) ) == string.len( s1 ) )
print( "s1 ends with s3: ", select( 2, string.find( s1, s3 ) ) == string.len( s1 ) )
M2000 Interpreter
Old versions need $ at the end of a variable name for strings. Newer versions don't it (this not hold for internal functions like Left$() there is no left() function).
Module StringMatch {
A$="Hello World"
Print A$ ~ "Hello*"
Print A$ ~ "*llo*"
p=Instr(A$, "llo")
Print p=3
\\ Handle multiple occurance for "o"
p=Instr(A$, "o")
While p > 0 {
Print "position:";p;{ for "o"}
p=Instr(A$, "o", p+1)
}
Print A$ ~ "*orld"
}
StringMatch
Module StringMatch {
A="Hello World"
Print A ~ "Hello*"
Print A ~ "*llo*"
p=Instr(A, "llo")
Print p=3
\\ Handle multiple occurance for "o"
p=Instr(A, "o")
While p > 0 {
Print "position:";p;{ for "o"}
p=Instr(A, "o", p+1)
}
Print A ~ "*orld"
}
StringMatch
- Output:
True
True
True
position:5 for "o"
position:8 for "o"
True
Maple
These facilities are all to be found in the StringTools package in Maple.
> with( StringTools ): # bind package exports at the top-level
> s := "dzrIemaWWIMidXYZwGiqkOOn":
> s[1..4]; # pick a prefix
"dzrI"
> IsPrefix( s[ 1 .. 4 ], s ); # check it
true
> s[ -4 .. -1 ]; # pick a suffix
"kOOn"
> IsSuffix( s[ -4 .. -1 ], s ); # check it
true
> p := Search( "XYZ", s ); # find a substring
p := 14
> s[ p .. p + 2 ]; # check
"XYZ"
> SearchAll( [ "WWI", "XYZ" ], s ); # search for multiple patterns
[8, 1], [14, 2]
> to 3 do s := cat( s, s ) end: length( s ); # build a longer string by repeated doubling
192
> p := SearchAll( "XYZ", s ); # find all occurrences
p := 14, 38, 62, 86, 110, 134, 158, 182
> {seq}( s[ i .. i + 2 ], i = p ); # check them
{"XYZ"}The StringTools package also contains facilities for regular expression matching, but for fixed string patterns, the Search and SearchAll tools are much faster.
Mathematica /Wolfram Language
StartWith[x_, y_] := MemberQ[Flatten[StringPosition[x, y]], 1]
EndWith[x_, y_] := MemberQ[Flatten[StringPosition[x, y]], StringLength[x]]
StartWith["XYZaaabXYZaaaaXYZXYZ", "XYZ"]
EndWith["XYZaaabXYZaaaaXYZXYZ", "XYZ"]
StringPosition["XYZaaabXYZaaaaXYZXYZ", "XYZ"]
- Output:
True
True
{{1,3},{8,10},{15,17},{18,20}}
MATLAB / Octave
% 1. Determining if the first string starts with second string
strcmp(str1,str2,length(str2))
% 2. Determining if the first string contains the second string at any location
~isempty(strfind(s1,s2))
% 3. Determining if the first string ends with the second string
( (length(str1)>=length(str2)) && strcmp(str1(end+[1-length(str2):0]),str2) )
% 1. Print the location of the match for part 2
disp(strfind(s1,s2))
% 2. Handle multiple occurrences of a string for part 2.
ix = strfind(s1,s2); % ix is a vector containing the starting positions of s2 within s1
min
One way might be:
(indexof 0 ==) :starts-with?
(indexof -1 !=) :contains?
((/ $/) swap 1 insert "" join regex ("") !=) :ends-with?
"minimalistic" "min" starts-with? puts!
"minimalistic" "list" contains? puts!
"minimalistic" "list" ends-with? puts!- Output:
true true false
MiniScript
We first extend the built-in string class with three new methods, and then demonstrate their use on some sample strings.
string.startsWith = function(s)
return self.len >= s.len and s[:s.len] == s
end function
string.endsWith = function(s)
return self.len >= s.len and s[-s.len:] == s
end function
string.findAll = function(s)
result = []
after = null
while true
foundPos = self.indexOf(s, after)
if foundPos == null then return result
result.push foundPos
after = foundPos + s.len - 1
end while
end function
first = "The brown dog jumped jumped and jumped"
second = "jumped"
firstQ = """" + first + """" // (first string, in quotes)
secondQ = """" + second + """"
doesOrNot = [" does not ", " does "]
print firstQ + doesOrNot[first.startsWith(second)] + "start with " + secondQ
print
found = first.findAll(second)
if not found then
print firstQ + " does not contain " + secondQ + " anywhere"
else
for pos in found
print firstQ + " is found at position " + pos + " in " + secondQ
end for
end if
print
print firstQ + doesOrNot[first.endsWith(second)] + "end with " + secondQ
- Output:
"The brown dog jumped jumped and jumped" does start with "jumped" "The brown dog jumped jumped and jumped" is found at position 14 in "jumped" "The brown dog jumped jumped and jumped" is found at position 21 in "jumped" "The brown dog jumped jumped and jumped" is found at position 32 in "jumped" "The brown dog jumped jumped and jumped" does end with "jumped"
MIPS Assembly
The function below returns the zero-based index where the string pointed to by $a1 occurs in $a0.
- If it returns strlen($a0), then $a1 was not found.
- If it returns 0, then $a0 begins with $a1.
- If it returns strlen($a0)-strlen($a1), then $a0 ends with $a1.
- Otherwise, $a0 contains $a1 starting at the specified location.
- Multiple occurrences can be detected by adding the output to $a0 and repeating the process; this is left as an exercise to the reader.
InString:
;input: $a0 = ptr to string 1
; $a1 = ptr to string 2
; assumes len($a1) <= len($a0)
;out: $v0 = zero-based index where the second string is placed in the first.
;clobbers: $t0,$t1
subiu sp,sp,4 ;set up a stack frame of 4 bytes.
sw $a1,(sp)
li $v0,0
InString_again:
lbu $t0,($a0)
nop
beqz $t0,InString_terminated
nop
lbu $t1,($a1)
nop
beqz $t1,InString_terminated
nop
bne $t0,$t1,InString_noMatch
nop
b InString_overhead
addiu $a1,1
InString_noMatch:
lw $a1,(sp) ;reset the substring pointer if the letters don't match
addiu $v0,1 ;load delay slot
InString_overhead:
addiu $a0,1
b InString_Again
nop
InString_terminated:
addiu sp,sp,4
jr ra
nop
- Output:
main:
la $a0,MyString
la $a1,Test1 ;this code was recompiled 5 times, testing a different string each time.
jal InString
nop
jal Monitor
nop
shutdown:
nop ;Project 64 will detect an infinite loop and close the ROM if I don't have this nop here.
b shutdown
nop
MyString: ;this was loaded into $a0
.ascii "abcdefghijklmnopqrstuvwxyz"
.byte 0
.align 4
;each of these was loaded into $a1 individually for testing
Test1:
.ascii "abc" ;InString returned 0
.byte 0
.align 4
Test2:
.ascii "xyz" ;InString returned 0x17 (decimal 23)
.byte 0
.align 4
Test3:
.ascii "def" ;InString returned 3
.byte 0
.align 4
Test4:
.ascii "z",0 ;InString returned 0x19 (decimal 25)
.byte 0
.align 4
Test5:
.ascii "1",0 ;InString returned 0x1A (decimal 26)
.byte 0
.align 4
NetRexx
/* NetRexx */
options replace format comments java crossref savelog symbols
lipsum = ''
x_ = 0
x_ = x_ + 1; lipsum[0] = x_; lipsum[x_] = 'Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.'
x_ = x_ + 1; lipsum[0] = x_; lipsum[x_] = lipsum[1].reverse
srch = ''
srch[1] = 'Lorem ipsum dolor sit amet'
srch[2] = 'consectetur adipisicing elit'
srch[3] = 'dolore magna aliqua.'
loop j_ = 1 to lipsum[0]
x1 = lipsum[j_].pos(srch[1])
x2 = lipsum[j_].pos(srch[2])
x3 = lipsum[j_].lastpos(srch[3])
report(x1 = 1, lipsum[j_], srch[1], 'Test string starts with search string:', 'Test string does not start with search string:')
report(x2 > 0, lipsum[j_], srch[2], 'Search string located in test string at position:' x2, 'Search string not found within test string:')
report(x3 \= srch[3].length, lipsum[j_], srch[3], 'Test string ends with search string:', 'Test string does not start with search string:')
end j_
many = ''
x_ = 0
x_ = x_ + 1; many[0] = x_; many[x_] = 'How many times does "many times" occur in this string?'
x_ = x_ + 1; many[0] = x_; many[x_] = 'How often does "many times" occur in this string?'
x_ = x_ + 1; many[0] = x_; many[x_] = 'How often does it occur in this string?'
srch[4] = 'many times'
loop j_ = 1 to many[0]
o_ = 0
k_ = 0
loop label dups until o_ = 0
o_ = many[j_].pos(srch[4], o_ + 1)
if o_ \= 0 then k_ = k_ + 1
end dups
report(k_ > 0, many[j_], srch[4], 'Number of times search string occurs:' k_, 'Search string not found')
end j_
method report(state = boolean, ts, ss, testSuccess, testFailure) public static
if state then say testSuccess
else say testFailure
say ' Test string:' ts
say ' Search string:' ss
say
return
NewLISP
(setq str "abcdefbcghi")
;; test if str starts with "ab"
(starts-with str "ab")
;; find "bc" inside str
(find "bc" str)
;; test if str ends with "ghi"
(ends-with str "ghi")
;; find all positions of pattern inside str
(define (find-all-pos pattern str)
(let ((idx -1) (pos '()))
(while (setq idx (find pattern str 0 (+ idx 1)))
(push idx pos -1))))
(find-all-pos "bc" str)
Nim
import strutils
let s = "The quick brown fox"
if s.startsWith("The quick"):
echo "Starts with “The quick”."
if s.endsWith("brown Fox"):
echo "Ends with “brown fox”."
if s.contains(" brown "):
echo "Contains “ brown ”."
if "quick" in s:
echo "Contains “quick”." # Alternate form for "contains".
let pos = find(s, " brown ") # -1 if not found.
if pos >= 0:
echo "“ brown ” is located at position: " & $pos
- Output:
Starts with “The quick”. Contains “ brown ”. Contains “quick”. “ brown ” is located at position: 9
Objeck
bundle Default {
class Matching {
function : Main(args : System.String[]) ~ Nil {
"abcd"->StartsWith("ab")->PrintLine(); # returns true
"abcd"->EndsWith("zn")->PrintLine(); # returns false
("abab"->Find("bb") <> -1)->PrintLine(); # returns false
("abab"->Find("ab") <> -1)->PrintLine(); # returns true
loc := "abab"->Find("bb"); # returns -1
loc := "abab"->Find("ab"); # returns 0
loc := "abab"->Find("ab", loc + 1); # returns 2
}
}
}Objective-C
[@"abcd" hasPrefix:@"ab"] //returns true
[@"abcd" hasSuffix:@"zn"] //returns false
int loc = [@"abab" rangeOfString:@"bb"].location //returns -1
loc = [@"abab" rangeOfString:@"ab"].location //returns 0
loc = [@"abab" rangeOfString:@"ab" options:0 range:NSMakeRange(loc+1, [@"abab" length]-(loc+1))].location //returns 2
OCaml
let match1 s1 s2 =
let len1 = String.length s1
and len2 = String.length s2 in
if len1 < len2 then false else
let sub = String.sub s1 0 len2 in
(sub = s2)
testing in the top-level:
# match1 "Hello" "Hello World!" ;; - : bool = false # match1 "Hello World!" "Hello" ;; - : bool = true
let match2 s1 s2 =
let len1 = String.length s1
and len2 = String.length s2 in
if len1 < len2 then false else
let rec aux i =
if i < 0 then false else
let sub = String.sub s1 i len2 in
if (sub = s2) then true else aux (pred i)
in
aux (len1 - len2)
# match2 "It's raining, Hello World!" "umbrella" ;; - : bool = false # match2 "It's raining, Hello World!" "Hello" ;; - : bool = true
let match3 s1 s2 =
let len1 = String.length s1
and len2 = String.length s2 in
if len1 < len2 then false else
let sub = String.sub s1 (len1 - len2) len2 in
(sub = s2)
# match3 "Hello World" "Hello" ;; - : bool = false # match3 "Hello World" "World" ;; - : bool = true
let match2_loc s1 s2 =
let len1 = String.length s1
and len2 = String.length s2 in
if len1 < len2 then (false, -1) else
let rec aux i =
if i < 0 then (false, -1) else
let sub = String.sub s1 i len2 in
if (sub = s2) then (true, i) else aux (pred i)
in
aux (len1 - len2)
# match2_loc "The sun's shining, Hello World!" "raining" ;; - : bool * int = (false, -1) # match2_loc "The sun's shining, Hello World!" "shining" ;; - : bool * int = (true, 10)
let match2_num s1 s2 =
let len1 = String.length s1
and len2 = String.length s2 in
if len1 < len2 then (false, 0) else
let rec aux i n =
if i < 0 then (n <> 0, n) else
let sub = String.sub s1 i len2 in
if (sub = s2)
then aux (pred i) (succ n)
else aux (pred i) (n)
in
aux (len1 - len2) 0
# match2_num "This cloud looks like a camel, \
that other cloud looks like a llama" "stone" ;;
- : bool * int = (false, 0)
# match2_num "This cloud looks like a camel, \
that other cloud looks like a llama" "cloud" ;;
- : bool * int = (true, 2)
Odin
The first example satisfies the 3 basic requirements.
package main
import "core:fmt"
import "core:strings"
main :: proc() {
using strings
s := "Hello world"
fmt.println(has_prefix(s, "He"), contains(s, "wo"), has_suffix(s, "ld"))
// Output: true true true
fmt.println(index(s, "wo"))
// Output: 6
}
The second example, adapted from the Go version, also satisfies the optional requirements.
package main
import "core:fmt"
import "core:strings"
main :: proc() {
using strings
s := "abracadabra"
s1 := "abr"
fmt.println( "1. ", s, " starts with ", s1, " --> ", has_prefix(s, s1))
fmt.println( "2. ", s, " contains ", s1, " --> ", contains (s, s1))
ndx := index(s, s1)
if ndx > -1 {
fmt.println(" 2.1. at location -> ", ndx)
ndx += len(s1)
for ndx < len(s) {
found := index(s[ndx:], s1)
if found > -1 {
fmt.println(" 2.2. at location -> ", found+ndx)
ndx += found+len(s1)
} else {
break
}
}
fmt.println(" 2.2. and that's all.")
}
fmt.println( "3. ", s, " ends with ", s1, " --> ", has_suffix(s, s1))
}
- Output:
1. abracadabra starts with abr --> true 2. abracadabra contains abr --> true 2.1. at location -> 0 2.2. at location -> 7 2.2. and that's all. 3. abracadabra ends with abr --> false
Oforth
: stringMatching(s1, s2)
| i |
s2 isAllAt(s1, 1) ifTrue: [ System.Out s1 << " begins with " << s2 << cr ]
s2 isAllAt(s1, s1 size s2 size - 1 + ) ifTrue: [ System.Out s1 << " ends with " << s2 << cr ]
s1 indexOfAll(s2) ->i
i ifNotNull: [ System.Out s1 << " includes " << s2 << " at position : " << i << cr ]
"\nAll positions : " println
1 ->i
while (s1 indexOfAllFrom(s2, i) dup ->i notNull) [
System.Out s1 << " includes " << s2 << " at position : " << i << cr
i s2 size + ->i
] ;- Output:
> "arduinoardblobard", "ard" stringMatching arduinoardblobard begins with ard arduinoardblobard ends with ard arduinoardblobard includes ard at position : 1 All positions : arduinoardblobard includes ard at position : 1 arduinoardblobard includes ard at position : 8 arduinoardblobard includes ard at position : 15
OxygenBasic
string s="sdfkjhgsdfkdfgkbopefioqwurti487sdfkrglkjfs9wrtgjglsdfkdkjcnmmb.,msfjflkjsdfk"
string f="sdfk"
string cr=chr(13)+chr(10),tab=chr(9)
string pr="FIND STRING LOCATIONS" cr cr
sys a=0, b=1, count=0, ls=len(s), lf=len(f)
do
a=instr b,s,f
if a=0 then exit do
count++
if a=1 then pr+="Begins with keyword" cr
pr+=count tab a cr
if a=ls-lf+1 then pr+="Ends with keyword at " a cr
b=a+1
end do
pr+=cr "Total matches: " count cr
print pr
'FIND STRING LOCATIONS
'
'Begins with keyword
'1 1
'2 8
'3 32
'4 51
'5 73
'Ends with keyword at 73
'
'Total matches: 5PARI/GP
This meets the first but not the second of the optional requirements. Note that GP treats any nonzero value as true so the location found by contains() can be ignore if not needed.
startsWith(string, prefix)={
string=Vec(string);
prefix=Vec(prefix);
if(#prefix > #string, return(0));
for(i=1,#prefix,if(prefix[i]!=string[i], return(0)));
1
};
contains(string, inner)={
my(good);
string=Vec(string);
inner=Vec(inner);
for(i=0,#string-#inner,
good=1;
for(j=1,#inner,
if(inner[j]!=string[i+j], good=0; break)
);
if(good, return(i+1))
);
0
};
endsWith(string, suffix)={
string=Vec(string);
suffix=Vec(suffix);
if(#suffix > #string, return(0));
for(i=1,#suffix,if(prefix[i]!=string[i+#string-#suffix], return(0)));
1
};PascalABC.NET
##
Println('abcd'.StartsWith('ab'));
Println('abcd'.EndsWith('cd'));
var abra := 'abracadabra';
Println('bra' in abra);
var ind := abra.IndexOf('bra');
var ind1 := abra.IndexOf('bra', ind + 1);
Println(ind,ind1);
abra.Matches('bra').Select(m -> m.Index).Println
- Output:
True True True 1 8 1 8
Perl
Using regexes:
$str1 =~ /^\Q$str2\E/ # true if $str1 starts with $str2
$str1 =~ /\Q$str2\E/ # true if $str1 contains $str2
$str1 =~ /\Q$str2\E$/ # true if $str1 ends with $str2
Using index:
index($str1, $str2) == 0 # true if $str1 starts with $str2
index($str1, $str2) != -1 # true if $str1 contains $str2
rindex($str1, $str2) == length($str1) - length($str2) # true if $str1 ends with $str2
Using substr:
substr($str1, 0, length($str2)) eq $str2 # true if $str1 starts with $str2
substr($str1, - length($str2)) eq $str2 # true if $str1 ends with $str2
Bonus task (printing all positions where $str2 appears in $str1):
print $-[0], "\n" while $str1 =~ /\Q$str2\E/g; # using a regex
my $i = -1; print $i, "\n" while ($i = index $str1, $str2, $i + 1) != -1; # using index
Phix
constant word = "the", -- (also try this with "th"/"he") sentence = "the last thing the man said was the" -- sentence = "thelastthingthemansaidwasthe" -- (practically the same results) -- A common, but potentially inefficient idiom for checking for a substring at the start is: if match(word,sentence)=1 then ?"yes(1)" end if -- A more efficient method is to test the appropriate slice if length(sentence)>=length(word) and sentence[1..length(word)]=word then ?"yes(2)" end if -- Which is almost identical to checking for a word at the end if length(sentence)>=length(word) and sentence[-length(word)..-1]=word then ?"yes(3)" end if -- Or sometimes you will see this, a tiny bit more efficient: if length(sentence)>=length(word) and match(word,sentence,length(sentence)-length(word)+1) then ?"yes(4)" end if -- Finding all occurences is a snap: integer r = match(word,sentence) while r!=0 do ?r r = match(word,sentence,r+1) end while -- or equivalently: ?match_all(word,sentence)
- Output:
"yes(1)"
"yes(2)"
"yes(3)"
"yes(4)"
1
16
33
{1,16,33}
Phixmonti
Simple solution
/# Rosetta Code problem: https://rosettacode.org/wiki/String_prepend
by Galileo, 11/2022 #/
include ..\Utilitys.pmt
"the last thing the man said was the" "the" pstack
len var l >ps
1 l slice tps == if "Begins with keyword" ? endif
0 l - l slice tps == if "Ends with keyword" ? endif
tail ps> find dup if "Keyword appears first at " print 1 + print " position" ? else drop endif
drop- Output:
["the last thing the man said was the", "the"] Begins with keyword Ends with keyword Keyword appears first at 16 position === Press any key to exit ===
More complex solution
/# Rosetta Code problem: https://rosettacode.org/wiki/String_prepend
by Galileo, 11/2022 #/
include ..\Utilitys.pmt
"the last thing the man said was the" "the" pstack
( ) rot rot >ps
true while
tps find dup >ps
if swap tps 0 put swap 32 ps> set true else ps> endif
endwhile
len ps> len nip - 1 + >ps drop
len for get
dup 1 == if "Begins with keyword" ? drop else
dup tps == if "Ends with keyword" ? drop else
"Locate at position " print ?
endif endif
endfor
ps> drop- Output:
["the last thing the man said was the", "the"] Begins with keyword Locate at position 16 Ends with keyword === Press any key to exit ===
PHP
<?php
/**********************************************************************************
* This program gets needle and haystack from the caller (chm.html) (see below)
* and checks for occurrences of the needle in the haystack
* 02.05.2013 Walter Pachl
* Comments or Suggestions welcome
**********************************************************************************/
$haystack = $_POST['haystack']; if ($haystack=='') {$haystack='no haystack given';}
$needle = $_POST['needle']; if ($needle=='') {$needle='no needle given';}
function rexxpos($h,$n) {
$pos = strpos($h,$n);
if ($pos === false) { $pos=-1; }
else { $pos=$pos+1; }
return ($pos);
}
$pos=rexxpos($haystack,$needle);
$tx1 = "";
if ($pos==-1){ $n=0; } // not found
else { $n=1; } // found once (so far)
// Special cases
if ($pos==1){ $tx1="needle found to be the start of the haystack"; }
if ($pos==strlen($haystack)-strlen($needle)+1)
{ $tx1="needle found at end of haystack"; }
if ($n>0) { // look for other occurrences
$pl=$pos; // list of positions
$p=$pos; //
$x="*************************************";
$h=$haystack;
while ($p>0) {
$h=substr($x,0,$p).substr($h,$p);
$p=rexxpos($h,$needle);
if ( $p>0 ) { $n=$n+1; $pl=$pl.", ".$p; }
}
if ($n==1) { $txt="needle found once in haystack, position: $pl."; }
else if ($n==2) { $txt="needle found twice in haystack, position(s): $pl."; }
else { $txt="needle found $n times in haystack, position(s): $pl."; }
}
else { $txt="needle not found in haystack."; }
?>
<html>
<head>
<title>Character Matching</title>
<meta name="author" content="Walter Pachl">
<meta name="date" content="02.05.2013">
<style>
p { font: 120% courier; }
</style>
</head>
<body>
<p><strong>Haystack: '<?php echo "$haystack" ?>'</strong></p>
<p><strong>Needle: '<?php echo "$needle" ?>'</strong></p>
<p><strong><?php echo "$txt" ?></strong></p>
<!-- special message: -->
<p style="color: red";><strong><?php echo "$tx1" ?></strong></p>
</body>
</html>
<?php
<!DOCTYPE html>
<!--
/************************************************************************
* Here we prompt the user for a haystack and a needle
* We then invoke program chmx.php
* to check for occurrences of the needle in the haystack
* 02.05.2013 Walter Pachl
* Comments or Suggestions welcome
************************************************************************/
-->
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>Character matching</title>
</head>
<body>
<form id="test" name="test" method="post" action="chmx.php">
<h1>Character matching</h1>
<p>Given two strings, demonstrate the following 3 types of matchings:
<ol style="margin-top:2; margin-bottom:2;">
<li>Determining if the first string starts with second string
<li>Determining if the first string contains the second string at any location
<li>Determining if the first string ends with the second string
</ol>
<p>Optional requirements:
<ol style="margin-top:2; margin-bottom:2;">
<li>Print the location of the match(es) for part 2
<li>Handle multiple occurrences of a string for part 2.
</ol>
<p style="margin-top:5; margin-bottom:3;">
<font face="Courier"><strong>Haystack:</strong>
<strong><input type="text" name="haystack" size="80"></strong></font></p>
<p style="margin-top:5; margin-bottom:3;">
<font face="Courier"><strong>Needle: </strong>
<strong><input type="text" name="needle" size="80"></strong></font></p>
<p>Press <input name="Submit" type="submit" class="erfolg" value="CHECK"/>
to invoke chmx.php.</p>
</form>
</body>
</html>
Picat
The two most common predicate to use for string matching is find/4 (find a substring) or append/3 (a general purpose reversible predicate for concatenating/splitting lists/strings). Both predicates are non-deterministic and can yield multiple solutions, e.g. together with findall/2.
import util.
go =>
S1 = "string second",
S2 = "string",
% - Determining if the first string starts with second string
println("Using find/4"),
if find(S1,S2,1,_) then
println("S1 starts with S2")
else
println("S1 does not start with S2")
end,
println("Using append/3"),
if append(S2,_,S1) then
println("S1 starts with S2")
else
println("S1 does not start with S2")
end,
% - Determining if the first string contains the second string at any location
S3 = "this is a string",
S4 = "is a",
if find(S3,S4,Start4,End4) then
printf("S3 contains S4 at pos %d..%d\n", Start4,End4)
else
println("S3 does not contain S4")
end,
% - Determining if the first string ends with the second string
S5 = "this is a string",
S6 = "string",
if find(S5,S6,Start6,S5.length) then
printf("S5 ends with S6, startpos: %d\n",Start6)
else
println("S5 does not end with S6")
end,
if append(_,S6,S5) then
println("S5 ends with S6")
else
println("S5 does not end with S6")
end,
S7 = "this is a string or a string",
S8 = "a string",
All = findall([Start8,End8], find(S7,S8,Start8,End8)),
println(positions=All),
% searching for " "
All2 = findall([Start9,End9], find(S7," ",Start9,End9)),
println(positions=All2),
nl.- Output:
Using find/4 S1 starts with S2 Using append/3 S1 starts with S2 S3 contains S4 at pos 6..9 S5 ends with S6, startpos: 11 S5 ends with S6 positions = [[9,16],[21,28]] positions = [[5,5],[8,8],[10,10],[17,17],[20,20],[22,22]]
PicoLisp
: (pre? "ab" "abcd")
-> "abcd"
: (pre? "xy" "abcd")
-> NIL
: (sub? "bc" "abcd")
-> "abcd"
: (sub? "xy" "abcd")
-> NIL
: (tail (chop "cd") (chop "abcd"))
-> ("c" "d")
: (tail (chop "xy") (chop "abcd"))
-> NIL
(de positions (Pat Str)
(setq Pat (chop Pat))
(make
(for ((I . L) (chop Str) L (cdr L))
(and (head Pat L) (link I)) ) ) )
: (positions "bc" "abcdabcd")
-> (2 6)PL/I
/* Let s be one string, t be the other that might exist within s. */
/* 8-1-2011 */
k = index(s, t);
if k = 0 then put skip edit (t, ' is nowhere in sight') (a);
else if k = 1 then
put skip edit (t, ' starts at the beginning of ', s) (a);
else if k+length(t)-1 = length(s) then
put skip edit (t, ' is at the end of ', s) (a);
else put skip edit (t, ' is within ', s) (a);
if k > 0 then put skip edit (t, ' starts at position ', k) (a);Optional extra:
/* Handle multiple occurrences. */
n = 1;
do forever;
k = index(s, t, n);
if k = 0 then
do;
if n = 1 then put skip list (t, ' is nowhere in sight');
stop;
end;
else if k = 1 then
put skip edit ('<', t, '> starts at the beginning of ', s) (a);
else if k+length(t)-1 = length(s) then
put skip edit ('<', t, '> is at the end of ', s) (a);
else put skip edit ('<', t, '> is within ', s) (a);
n = k + length(t);
if k > 0 then
put skip edit ('<', t, '> starts at position ', trim(k)) (a);
else stop;
end;PowerShell
"spicywiener".StartsWith("spicy")
"spicywiener".Contains("icy")
"spicywiener".EndsWith("wiener")
"spicywiener".IndexOf("icy")
[regex]::Matches("spicywiener", "i").count
- Output:
True True True 2 2
Prolog
:- system:set_prolog_flag(double_quotes,codes) .
:- [library(lists)] .
%! starts_with(FIRSTz,SECONDz)
%
% True if `SECONDz` is the beginning of `FIRSTz` .
starts_with(FIRSTz,SECONDz)
:-
lists:append(SECONDz,_,FIRSTz)
.
%! contains(FIRSTz,SECONDz)
%
% True once if `SECONDz` is contained within `FIRSTz` at one or more positions .
contains(FIRSTz,SECONDz)
:-
contains(FIRSTz,SECONDz,_) ,
!
.
%! contains(FIRSTz,SECONDz,NTH1)
%
% True if `SECONDz` is contained within `FIRSTz` at position `NTH1` .
contains(FIRSTz,SECONDz,NTH1)
:-
lists:append([PREFIXz,SECONDz,_SUFFIXz_],FIRSTz) ,
prolog:length(PREFIXz,NTH0) ,
NTH1 is NTH0 + 1
.
%! ends_with(FIRSTz,SECONDz)
%
% True if `SECONDz` is the ending of `FIRSTz` .
ends_with(FIRSTz,SECONDz)
:-
lists:append(_,SECONDz,FIRSTz)
.- Output:
?- starts_with("abcdef","abc") .
true .
?- starts_with("abc","abc") .
true .
?- starts_with("abc","abcd") .
false .
?- starts_with("dabc","abc") .
false .
?- starts_with("","") .
true .
?-
?- contains("abcdef","abc") .
true.
?- contains("abcdef","abc",NTH).
NTH = 1 ;
false.
?- contains("abcdef","de",NTH).
NTH = 4 ;
false.
?- contains("abcdef","f",NTH).
NTH = 6 ;
false.
?- contains("abcde","f",NTH).
false.
?- contains("","",NTH).
NTH = 1 ; % wtf ?
false.
?- contains("a","a",NTH).
NTH = 1 ; % wtf ?
false.
?-
?- ends_with("abc","abc") .
true ;
false .
?- ends_with("abc","bc") .
true ;
false .
?- ends_with("abcd","bc") .
false .
?- ends_with("","") .
true ;
false .
?-
PureBasic
Procedure StartsWith(String1$, String2$)
Protected Result
If FindString(String1$, String2$, 1) =1 ; E.g Found in possition 1
Result =CountString(String1$, String2$)
EndIf
ProcedureReturn Result
EndProcedure
Procedure EndsWith(String1$, String2$)
Protected Result, dl=Len(String1$)-Len(String2$)
If dl>=0 And Right(String1$, Len(String2$))=String2$
Result =CountString(String1$, String2$)
EndIf
ProcedureReturn Result
EndProcedureAnd a verification
If OpenConsole()
PrintN(Str(StartsWith("Rosettacode", "Rosetta"))) ; = 1
PrintN(Str(StartsWith("Rosettacode", "code"))) ; = 0
PrintN(Str(StartsWith("eleutherodactylus cruralis", "e"))) ; = 3
PrintN(Str(EndsWith ("Rosettacode", "Rosetta"))) ; = 0
PrintN(Str(EndsWith ("Rosettacode", "code"))) ; = 1
PrintN(Str(EndsWith ("Rosettacode", "e"))) ; = 2
Print(#CRLF$ + #CRLF$ + "Press ENTER to exit"): Input()
CloseConsole()
EndIfAn alternate and more complete solution:
Procedure startsWith(string1$, string2$)
;returns one if string1$ starts with string2$, otherwise returns zero
If FindString(string1$, string2$, 1) = 1
ProcedureReturn 1
EndIf
ProcedureReturn 0
EndProcedure
Procedure contains(string1$, string2$, location = 0)
;returns the location of the next occurrence of string2$ in string1$ starting from location,
;or zero if no remaining occurrences of string2$ are found in string1$
ProcedureReturn FindString(string1$, string2$, location + 1)
EndProcedure
Procedure endsWith(string1$, string2$)
;returns one if string1$ ends with string2$, otherwise returns zero
Protected ls = Len(string2$)
If Len(string1$) - ls >= 0 And Right(string1$, ls) = string2$
ProcedureReturn 1
EndIf
ProcedureReturn 0
EndProcedure
If OpenConsole()
PrintN(Str(startsWith("RosettaCode", "Rosetta"))) ; = 1, true
PrintN(Str(startsWith("RosettaCode", "Code"))) ; = 0, false
PrintN("")
PrintN(Str(contains("RosettaCode", "luck"))) ; = 0, no occurrences
Define location
Repeat
location = contains("eleutherodactylus cruralis", "e", location)
PrintN(Str(location)) ;display each occurrence: 1, 3, 7, & 0 (no more occurrences)
Until location = 0
PrintN("")
PrintN(Str(endsWith ("RosettaCode", "Rosetta"))) ; = 0, false
PrintN(Str(endsWith ("RosettaCode", "Code"))) ; = 1, true
Print(#CRLF$ + #CRLF$ + "Press ENTER to exit"): Input()
CloseConsole()
EndIf- Output:
1 0 0 1 3 7 0 0 1
Python
"abcd".startswith("ab") #returns True
"abcd".endswith("zn") #returns False
"bb" in "abab" #returns False
"ab" in "abab" #returns True
loc = "abab".find("bb") #returns -1
loc = "abab".find("ab") #returns 0
loc = "abab".find("ab",loc+1) #returns 2QB64
DefStr S
DefInt P
string2 = "dogs"
string1 = "dogs and cats are often enemies,because dogs are stronger than cats, but cats sometimes can be friend to dogs"
position = 0
pcount = 0
Print "Searching "; string2; " into "; string1
While (InStr(position, string1, string2) > 0)
position = InStr(position + 1, string1, string2)
pcount = pcount + 1
If position = 1 Then Print string1; "- starts with -"; string2
Print position
If position = Len(string1) - Len(string2) + 1 Then
Print string1; "- ends with -"; string2
Exit While
End If
Wend
Print string2; " is present "; pcount; " times into "; string1Quackery
These work for any nests (i.e. dynamic arrays), not just strings (i.e. nests of chars).
[ tuck size split drop = ] is starts ( [ [ --> b )
[ tuck size negate split nip = ] is ends ( [ [ --> b )
[ 2dup = iff true
else
[ over [] = iff false done
2dup starts iff true done
dip behead nip again ]
dip 2drop ] is contains ( [ [ --> b )
[ iff
[ say "true" ]
else
[ say "false" ] ] is echobool ( b --> )
$ "abcdefgh" $ "abc" starts echobool cr
$ "abcdefgh" $ "xyz" starts echobool cr
$ "abcdefgh" $ "fgh" ends echobool cr
$ "abcdefgh" $ "xyz" ends echobool cr
$ "abcdefgh" $ "cde" contains echobool cr
$ "abcdefgh" $ "xyz" contains echobool cr- Output:
true false true false true false
Racket
#lang racket
(require srfi/13)
(string-prefix? "ab" "abcd")
(string-suffix? "cd" "abcd")
(string-contains "abab" "bb")
(string-contains "abab" "ba")- Output:
#t #t #f 1
Raku
(formerly Perl 6)
Using string methods:
$haystack.starts-with($needle) # True if $haystack starts with $needle
$haystack.contains($needle) # True if $haystack contains $needle
$haystack.ends-with($needle) # True if $haystack ends with $needleUsing regexes:
so $haystack ~~ /^ $needle / # True if $haystack starts with $needle
so $haystack ~~ / $needle / # True if $haystack contains $needle
so $haystack ~~ / $needle $/ # True if $haystack ends with $needleUsing substr:
substr($haystack, 0, $needle.chars) eq $needle # True if $haystack starts with $needle
substr($haystack, *-$needle.chars) eq $needle # True if $haystack ends with $needleBonus task:
$haystack.match($needle, :g)».from; # List of all positions where $needle appears in $haystack
$haystack.indices($needle :overlap); # Also find any overlapping instances of $needle in $haystackRetro
: startsWith? ( $1 $2 - f )
withLength &swap dip 0 swap ^strings'getSubset compare ;
"abcdefghijkl" "abcde" startsWith?
"abcdefghijkl" "bcd" startsWith?
"abcdefghijkl" "bcd" ^strings'search
"abcdefghijkl" "zmq" ^strings'search
: endsWith? ( $1 $2 - f )
swap withLength + over getLength - compare ;
"abcdefghijkl" "ijkl" endsWith?
"abcdefghijkl" "abc" endsWith?REXX
Extra coding was added to take care of using plurals in the last output message.
/*REXX program demonstrates some basic character string testing (for matching). */
parse arg A B /*obtain A and B from the command line.*/
say 'string A = ' A /*display string A to the terminal.*/
say 'string B = ' B /* " " B " " " */
say copies('░', 70) /*display a line separator (fence). */
LB= length(B) /*get the length of string B in bytes*/
if left(A, LB)==B then say 'string A starts with string B'
else say "string A doesn't start with string B"
say /* [↓] another method using COMPARE BIF*/
p= pos(B, A)
if p==0 then say "string A doesn't contain string B"
else say 'string A contains string B (starting in position' p")"
say
if right(A, LB)==B then say 'string A ends with string B'
else say "string A doesn't end with string B"
say
$=; p= 0; do until p==0; p= pos(B, A, p+1)
if p\==0 then $= $',' p
end /*until*/
$= space( strip($, 'L', ",") ) /*elide extra blanks and leading comma.*/
#= words($) /*obtain number of words in $ string.*/
if #==0 then say "string A doesn't contain string B"
else say 'string A contains string B ' # " time"left('s', #>1),
"(at position"left('s', #>1) $")" /*stick a fork in it, we're all done. */- output when the following is specified (the five Marx brothers): Chico_Harpo_Groucho_Zeppo_Gummo p
string A = Chico_Harpo_Groucho_Zeppo_Gummo string B = p ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ string A doesn't start with string B string A contains string B (starting in position 10) string A doesn't end with string B string A contains string B 3 times (at positions 10, 23, 24)
- output when the following is specified: Chico_Harpo_Groucho_Zeppo_Gummo Z
string A = Chico_Harpo_Groucho_Zeppo_Gummo string B = Z ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ string A doesn't start with string B string A contains string B (starting in position 21) string A doesn't end with string B string A contains string B 1 time (at position 21)
- output when the following is specified: Chico_Harpo_Groucho_Zeppo_Gummo Chi
string A = Chico_Harpo_Groucho_Zeppo_Gummo string B = Chi ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ string A starts with string B string A contains string B (starting in position 1) string A doesn't end with string B string A contains string B 1 time (at position 1)
- output when the following is specified: Chico_Harpo_Groucho_Zeppo_Gummo mmo
string A = Chico_Harpo_Groucho_Zeppo_Gummo string B = mmo ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ string A doesn't start with string B string A contains string B (starting in position 29) string A ends with string B string A contains string B 1 time (at position 29)
Ring
aString = "Welcome to the Ring Programming Language"
bString = "Ring"
bStringIndex = substr(aString,bString)
if bStringIndex > 0 see "" + bStringIndex + " : " + bString okRPL
Determining if the first string starts with second string
Returns 1 if the strings match accordingly, 0 otherwise.
"ABCDEF" "ABC" ≪ SWAP OVER SIZE 1 SWAP SUB == ≫ EVAL
Determining if the first string contains the second string at any location
Returns the position of the first character of the second string in the first string if the strings match accordingly, 0 otherwise.
"ABCDEF" "BCD" POS
Determining if the first string ends with the second string
Returns 1 if the strings match accordingly, 0 otherwise.
"ABCDEF" "DEF" ≪ SWAP DUP2 SIZE SWAP SIZE - 1 + OVER SIZE SUB == ≫ EVAL
- Output:
3: 1 2: 2 1: 1
Ruby
p 'abcd'.start_with?('ab') #returns true
p 'abcd'.end_with?('ab') #returns false
p 'abab'.include?('bb') #returns false
p 'abab'.include?('ab') #returns true
p 'abab'['bb'] #returns nil
p 'abab'['ab'] #returns "ab"
p 'abab'.index('bb') #returns nil
p 'abab'.index('ab') #returns 0
p 'abab'.index('ab', 1) #returns 2
p 'abab'.rindex('ab') #returns 2Run BASIC
s1$ = "abc def ghi klmnop"
s2$ = "abc" ' begins with
s3$ = "ef" ' is in the string
s4$ = "nop" ' ends with
sn2$ = "abcx" ' not begins with
sn3$ = "efx" ' not in the string
sn4$ = "nopx" ' not ends with
if left$(s1$,len(s2$)) <> s2$ then a$ = "Not "
print "String:";s1$;" does ";a$;"begin with:";s2$
if instr(s1$,s3$) = 0 then a$ = "Not "
print "String:";s1$;" does ";a$;"contain:";s3$
if mid$(s1$,len(s1$) + 1 - len(s4$),len(s4$)) <> s4$ then a$ = "Not "
print "String:";s1$;" does ";a$;"end with:";s4$
' ----------- not -----------------------------
print
if left$(s1$,len(sn2$)) <> sn2$ then a$ = "Not "
print "String:";s1$;" does ";a$;"begin with:";sn2$
if instr(s1$,sn3$) = 0 then a$ = "Not "
print "String:";s1$;" does ";a$;"contain:";sn3$
if mid$(s1$,len(s1$) + 1 - len(sn4$),len(sn4$)) <> sn4$ then a$ = "Not "
print "String:";s1$;" does ";a$;"end with:";sn4$- Output:
String:abc def ghi klmnop does begin with:abc String:abc def ghi klmnop does contain:ef String:abc def ghi klmnop does end with:nop String:abc def ghi klmnop does Not begin with:abcx String:abc def ghi klmnop does Not contain:efx String:abc def ghi klmnop does Not end with:nopx
Rust
fn print_match(possible_match: Option<usize>) {
match possible_match {
Some(match_pos) => println!("Found match at pos {}", match_pos),
None => println!("Did not find any matches")
}
}
fn main() {
let s1 = "abcd";
let s2 = "abab";
let s3 = "ab";
// Determining if the first string starts with second string
assert!(s1.starts_with(s3));
// Determining if the first string contains the second string at any location
assert!(s1.contains(s3));
// Print the location of the match
print_match(s1.find(s3)); // Found match at pos 0
print_match(s1.find(s2)); // Did not find any matches
// Determining if the first string ends with the second string
assert!(s2.ends_with(s3));
}fn main(){
let hello = String::from("Hello world");
println!(" Start with \"he\" {} \n Ends with \"rd\" {}\n Contains \"wi\" {}",
hello.starts_with("He"),
hello.ends_with("ld"),
hello.contains("wi"));
}- Output:
Start with "he" true Ends with "ld" true Contains "wi" false
Scala
"abcd".startsWith("ab") //returns true
"abcd".endsWith("zn") //returns false
"abab".contains("bb") //returns false
"abab".contains("ab") //returns true
var loc="abab".indexOf("bb") //returns -1
loc = "abab".indexOf("ab") //returns 0
loc = "abab".indexOf("ab", loc+1) //returns 2sed
The following programs handle the input lines pairwise: If the first string of a pair contains the second string, the former one is shown. (Which means that non-matching pairs are filtered out.)
1. Determining if the first string starts with the second string:
N;/^\(.*\).*\n\1$/!d;s/\n.*//2. Determining if the first string contains the second string at any location:
N;/.*\(.*\).*\n\1$/!d;s/\n.*//3. Determining if the first string ends with the second string:
N;/\(.*\)\n\1$/!d;s/\n.*//- Output:
$ printf '%s\n' abcd bcd wxyz wxy | sed -f match1.sed wxyz $ printf '%s\n' abcd be vwxyz wxy | sed -f match2.sed vwxyz $ printf '%s\n' abcd abc wxyz xyz | sed -f match3.sed wxyz
Seed7
$ include "seed7_05.s7i";
const proc: main is func
local
var integer: position is 0;
begin
writeln(startsWith("abcd", "ab")); # write TRUE
writeln(endsWith("abcd", "zn")); # write FALSE
writeln(pos("abab", "bb") <> 0); # write FALSE
writeln(pos("abab", "ab") <> 0); # write TRUE
writeln(pos("abab", "bb")); # write 0
position := pos("abab", "ab");
writeln(position); # position is 1
position := pos("abab", "ab", succ(position));
writeln(position); # position is 3
end func;- Output:
TRUE FALSE FALSE TRUE 0 1 3
Sidef
var first = "abc-abcdef-abcd";
var second = "abc";
say first.begins_with(second); #=> true
say first.contains(second); #=> true
say first.ends_with(second); #=> false
# Get and print the location of the match
say first.index(second); #=> 0
# Find multiple occurrences of a string
var pos = -1;
while (pos = first.index(second, pos+1) != -1) {
say "Match at pos: #{pos}";
}Smalltalk
a startsWith: b
a includesSubCollection: b. "inherited from superclass"
a includesString: b. "the same, but more readable"
a endsWith: b
a indexOfSubCollection: b "inherited"
a indexOfSubCollection: b startingAt: pos "inherited"
a indexOfString: b
a indexOfStringStartingAt: bSNOBOL4
s1 = 'abcdabefgab'
s2 = 'ab'
s3 = 'xy'
OUTPUT = ?(s1 ? POS(0) s2) "1. " s2 " begins " s1
OUTPUT = ?(s1 ? POS(0) s3) "1. " s3 " begins " s1 ;# fails
n = 0
again s1 POS(n) ARB s2 @a :F(p3)
OUTPUT = "2. " s2 " found at position "
+ a - SIZE(s2) " in " s1
n = a :(again)
p3 OUTPUT = ?(s1 ? s2 RPOS(0)) "3. " s2 " ends " s1
END- Output:
1. ab begins abcdabefgab 2. ab found at position 0 in abcdabefgab 2. ab found at position 4 in abcdabefgab 2. ab found at position 9 in abcdabefgab 3. ab ends abcdabefgab
Standard ML
String.isPrefix "ab" "abcd"; (* returns true *)
String.isSuffix "zn" "abcd"; (* returns false *)
String.isSubstring "bb" "abab"; (* returns false *)
String.isSubstring "ab" "abab"; (* returns true *)
#2 (Substring.base (#2 (Substring.position "bb" (Substring.full "abab")))); (* returns 4 *)
val loc = #2 (Substring.base (#2 (Substring.position "ab" (Substring.full "abab")))); (* returns 0 *)
val loc' = #2 (Substring.base (#2 (Substring.position "ab" (Substring.extract ("abab", loc+1, NONE))))); (* returns 2 *)Swift
var str = "Hello, playground"
str.hasPrefix("Hell") //True
str.hasPrefix("hell") //False
str.containsString("llo") //True
str.containsString("xxoo") //False
str.hasSuffix("playground") //True
str.hasSuffix("world") //FalseTailspin
This assumes the string to be found does not contain any regex special characters, otherwise we should work with composers (parsers) see below.
templates find&{s:}
when <'$s;.*'> do '$; starts with $s;' !
when <'.*$s;'> do '$; ends with $s;' !
when <'.*$s;.*'> do '$; contains $s;' !
otherwise '$s; cannot be found in $;' !
end find
'abcd' -> find&{s:'ab'} -> !OUT::write
'
' -> !OUT::write
'abcd' -> find&{s:'cd'} -> !OUT::write
'
' -> !OUT::write
'abcd' -> find&{s:'bc'} -> !OUT::write
'
' -> !OUT::write
'abcd' -> find&{s:'e'} -> !OUT::write- Output:
abcd starts with ab abcd ends with cd abcd contains bc e cannot be found in abcd
Working with composers and literal matchers to be able to handle any string.
composer startsWith&{s:}
@: 0;
(<='$s;'>? -> @:1; <'.*'>) $@
end startsWith
composer endsWith&{s:}
@: 0;
(<ends|'.*'>) $@
rule ends: (<'.'>* <='$s;'> -> @:1;)
end endsWith
composer contains&{s:}
@: 0;
(<~='$s;'>? <='$s;'>? -> @:1; <'.*'>) $@
end contains
templates find&{s:}
when <?($ -> startsWith&{s:$s} <=1>)> do '$; starts with $s;' !
when <?($ -> endsWith&{s:$s} <=1>)> do '$; ends with $s;' !
when <?($ -> contains&{s:$s} <=1>)> do '$; contains $s;' !
otherwise '$s; cannot be found in $;' !
end find
'abcd' -> find&{s:'ab'} -> !OUT::write
'
' -> !OUT::write
'abcd' -> find&{s:'cd'} -> !OUT::write
'
' -> !OUT::write
'abcd' -> find&{s:'bc'} -> !OUT::write
'
' -> !OUT::write
'abcd' -> find&{s:'e'} -> !OUT::write
'
' -> !OUT::write
'banana' -> find&{s:'na'} -> !OUT::write- Output:
abcd starts with ab abcd ends with cd abcd contains bc e cannot be found in abcd banana ends with na
In tailspin we don't manipulate strings by character indices but we can still work out the second part. String characters can be streamed and captured in an array, although we prefer to compare in strings, here with a composer (parser). This has also been crafted to work with strings containing special regex characters by using literal equality.
composer index&{s:}
@index: 0;
[<match>*]
rule match: ([<~='$s;'>? ...] -> @: $@ + 1 + $::length;) <'.'>? -> $@
end index
'ba is found in positions $:'banana' -> index&{s:'ba'}; in banana' -> !OUT::write
'
' -> !OUT::write
'ana is found in positions $:'banana' -> index&{s:'ana'}; in banana' -> !OUT::write
'
' -> !OUT::write
'c is found in positions $:'banana' -> index&{s:'c'}; in banana' -> !OUT::write- Output:
ba is found in positions [1] in banana ana is found in positions [2, 4] in banana c is found in positions [] in banana
Tcl
In this code, we are looking in various ways for the string in the variable needle in the string in the variable haystack.
set isPrefix [string equal -length [string length $needle] $haystack $needle]
set isContained [expr {[string first $needle $haystack] >= 0}]
set isSuffix [string equal $needle [string range $haystack end-[expr {[string length $needle]-1}] end]]Of course, in the cases where the needle is a glob-safe string (i.e., doesn't have any of the characters “*?[\” in), this can be written far more conveniently:
set isPrefix [string match $needle* $haystack]
set isContained [string match *$needle* $haystack]
set isSuffix [string match *$needle $haystack]Another powerful technique is to use the regular expression engine in literal string mode:
set isContained [regexp ***=$needle $haystack]This can be extended by getting the regexp to return the locations of the matches, enabling the other forms of match to be done:
set matchLocations [regexp -indices -all -inline ***=$needle $haystack]
# Each match location is a pair, being the index into the string where the needle started
# to match and the index where the needle finished matching
set isContained [expr {[llength $matchLocations] > 0}]
set isPrefix [expr {[lindex $matchLocations 0 0] == 0}]
set isSuffix [expr {[lindex $matchLocations end 1] == [string length $haystack]-1}]
set firstMatchStart [lindex $matchLocations 0 0]
puts "Found \"$needle\" in \"$haystack\" at $firstMatchStart"
foreach location $matchLocations {
puts "needle matched at index [lindex $location 0]"
}TUSCRIPT
$$ MODE TUSCRIPT
ASK "string1", string1=""
ASK "string2", string2=""
IF (string1.sw.string2) THEN
PRINT string1," starts with ",string2
ELSE
PRINT string1," not starts with ",string2
ENDIF
SET beg=STRING (string1,string2,0,0,0,end)
IF (beg!=0) THEN
PRINT string1," contains ",string2
PRINT " starting in position ",beg
PRINT " ending in position ",end
ELSE
PRINT string1," not contains ",string2
ENDIF
IF (string1.ew.string2) THEN
PRINT string1," ends with ",string2
ELSE
PRINT string1," not ends with ",string2
ENDIF- Output:
string1 >Rosetta Code string2 >Code Rosetta Code not starts with Code Rosetta Code contains Code starting in position 9 ending in position 13 Rosetta Code ends with Code
TXR
TXR Lisp
(tree-case *args*
((big small)
(cond
((< (length big) (length small))
(put-line `@big is shorter than @small`))
((str= big small)
(put-line `@big and @small are equal`))
((starts-with small big)
(put-line `@small is a prefix of @big`))
((ends-with small big)
(put-line `@small is a suffix of @big`))
(t (iflet ((pos (search-str big small)))
(put-line `@small occurs in @big at position @pos`)
(put-line `@small does not occur in @big`)))))
(otherwise
(put-line `usage: @(ldiff *full-args* *args*) <bigstring> <smallstring>`)))- Output:
$ txr cmatch2.tl x usage: txr cmatch2.tl <bigstring> <smallstring> $ txr cmatch2.tl x y z usage: txr cmatch2.tl <bigstring> <smallstring> $ txr cmatch2.tl catalog cat cat is a prefix of catalog $ txr cmatch2.tl catalog log log is a suffix of catalog $ txr cmatch2.tl catalog at at occurs in catalog at position 1 $ txr cmatch2.tl catalog catalogue catalog is shorter than catalogue $ txr cmatch2.tl catalog catalog catalog and catalog are equal $ txr cmatch2.tl catalog dog dog does not occur in catalog
Pattern Language
@line
@(cases)
@ line
@ (output)
second line is the same as first line
@ (end)
@(or)
@ (skip)@line
@ (output)
first line is a suffix of the second line
@ (end)
@(or)
@ line@(skip)
@ (output)
first line is a suffix of the second line
@ (end)
@(or)
@ prefix@line@(skip)
@ (output)
first line is embedded in the second line at position @(length prefix)
@ (end)
@(or)
@ (output)
first line is not found in the second line
@ (end)
@(end)- Output:
$ txr cmatch.txr - 123 01234 first line is embedded in the second line at position 1 $ txr cmatch.txr - 123 0123 first line is a suffix of the second line
Uiua
Does football start with foot?
⊢⦷"foot" "football" # 1Does football contain otba?
/↥⌕"otba" "football" # 1Does football end with ball?
⊢⇌⦷"ball" "football" # 1Where is iss in Mississippi?
⊚⌕"iss" "Mississippi" # [1 4]Vala
void main() {
var text = "一二三四五六七八九十";
var starts = "一二";
var ends = "九十";
var contains = "五六";
var not_contain = "百";
stdout.printf(@"text: $text\n\n", );
stdout.printf(@"starts with $starts: $(text.has_prefix(starts))\n");
stdout.printf(@"ends with $ends: $(text.has_suffix(ends))\n");
stdout.printf(@"starts with $starts: $(text.has_suffix(starts))\n");
stdout.printf(@"contains $contains: $(contains in text)\n");
stdout.printf(@"contains $not_contain: $(contains in text)\n");
}- Output:
text: 一二三四五六七八九十 starts with 一二: true ends with 九十: true starts with 一二: false contains 五六: true contains 百: false
VBA
Public Sub string_matching()
word = "the" '-- (also try this with "th"/"he")
sentence = "the last thing the man said was the"
'-- sentence = "thelastthingthemansaidwasthe" '-- (practically the same results)
'-- A common, but potentially inefficient idiom for checking for a substring at the start is:
If InStr(1, sentence, word) = 1 Then
Debug.Print "yes(1)"
End If
'-- A more efficient method is to test the appropriate slice
If Len(sentence) >= Len(word) _
And Mid(sentence, 1, Len(word)) = word Then
Debug.Print "yes(2)"
End If
'-- Which is almost identical to checking for a word at the end
If Len(sentence) >= Len(word) _
And Mid(sentence, Len(sentence) - Len(word) + 1, Len(word)) = word Then
Debug.Print "yes(3)"
End If
'-- Or sometimes you will see this, a tiny bit more efficient:
If Len(sentence) >= Len(word) _
And InStr(Len(sentence) - Len(word) + 1, sentence, word) Then
Debug.Print "yes(4)"
End If
'-- Finding all occurences is a snap:
r = InStr(1, sentence, word)
Do While r <> 0
Debug.Print r
r = InStr(r + 1, sentence, word)
Loop
End Sub- Output:
yes(1) yes(2) yes(3) yes(4) 1 16 33
VBScript
Function StartsWith(s1,s2)
StartsWith = False
If Left(s1,Len(s2)) = s2 Then
StartsWith = True
End If
End Function
Function Contains(s1,s2)
Contains = False
If InStr(1,s1,s2) Then
Contains = True & " at positions "
j = 1
Do Until InStr(j,s1,s2) = False
Contains = Contains & InStr(j,s1,s2) & ", "
If j = 1 Then
If Len(s2) = 1 Then
j = j + InStr(j,s1,s2)
Else
j = j + (InStr(j,s1,s2) + (Len(s2) - 1))
End If
Else
If Len(s2) = 1 Then
j = j + ((InStr(j,s1,s2) - j) + 1)
Else
j = j + ((InStr(j,s1,s2) - j) + (Len(s2) - 1))
End If
End If
Loop
End If
End Function
Function EndsWith(s1,s2)
EndsWith = False
If Right(s1,Len(s2)) = s2 Then
EndsWith = True
End If
End Function
WScript.StdOut.Write "Starts with test, 'foo' in 'foobar': " & StartsWith("foobar","foo")
WScript.StdOut.WriteLine
WScript.StdOut.Write "Contains test, 'o' in 'fooooobar': " & Contains("fooooobar","o")
WScript.StdOut.WriteLine
WScript.StdOut.Write "Ends with test, 'bar' in 'foobar': " & EndsWith("foobar","bar")- Output:
Starts with test, 'foo' in 'foobar': True Contains test, 'o' in 'fooooobar': True at positions 2, 3, 4, 5, 6, Ends with test, 'bar' in 'foobar': True
Visual Basic
works the same as in VBA, see String_matching#VBA
V (Vlang)
fn main() {
str := 'abcd'
println(str.starts_with('ab')) // True
println(str.ends_with('zn')) // False
println(str.contains('bb')) // False
println(str.contains('ab')) // True
println(str.index('bc') or {-1}) // 1 // V arrays are 0 based; first char position is 0
}- Output:
true false false true 1
Wren
var s = "abracadabra"
var t = "abra"
var u = "ra"
var v = "cad"
System.print("'%(s)' starts with '%(t)' is %(s.startsWith(t))")
var indices = []
var start = 0
while (true) {
var ix = s.indexOf(u, start)
if (ix >= 0) {
indices.add(ix)
start = ix + u.count
if (start >= s.count) break
} else break
}
var contained = indices.count > 0
System.print("'%(s)' contains '%(u)' is %(contained) %(contained ? "at indices %(indices)" : "")")
System.print("'%(s)' ends with '%(v)' is %(s.endsWith(v))")- Output:
'abracadabra' starts with 'abra' is true 'abracadabra' contains 'ra' is true at indices [2, 9] 'abracadabra' ends with 'cad' is false
XPL0
include c:\cxpl\codes; \intrinsic 'code' declarations
string 0; \use zero-terminated strings
func StrLen(A); \Return number of characters in a string
char A;
int I;
for I:= 0 to -1>>1-1 do
if A(I) = 0 then return I;
func StrFind(A, B); \Search for string B in string A
\Returns index of first occurrence of string B in A, or -1 if B is not found
char A, B; \strings to be compared
int LA, LB, I, J;
[LA:= StrLen(A);
LB:= StrLen(B);
for I:= 0 to LA-LB do
[for J:= 0 to LB-1 do
if B(J) # A(J+I) then J:= LB+1;
if J = LB then return I; \found
];
return -1;
];
char Str; int I, J;
[Str:= "pack my box with";
\ 0123456789012345
Text(0, if StrFind(Str, "pack") = 0 then "yes" else "no"); CrLf(0); \1.
Text(0, if StrFind(Str, "ack") = 0 then "yes" else "no"); CrLf(0);
I:= StrFind(Str, "x w");
Text(0, if I >= 0 then "yes" else "no"); \2.
Text(0, ", at offset "); IntOut(0, I); CrLf(0);
I:= 0; J:= 0; \offsets of space characters
loop [I:= StrFind(Str+J, " ");
if I < 0 then quit;
IntOut(0, I+J); ChOut(0, ^ );
J:= J+I+1;
];
CrLf(0);
Text(0, if StrFind(Str, "X w") >= 0 then "yes" else "no"); CrLf(0);
Text(0, if StrFind(Str, "with") = StrLen(Str)-StrLen("with") then "yes" else "no"); CrLf(0); \3.
Text(0, if StrFind(Str, "x w" ) = StrLen(Str)-StrLen("x w" ) then "yes" else "no"); CrLf(0);
]- Output:
yes no yes, at offset 10 4 7 11 no yes no
XProfan
// XProfan can use StringParts, so the results here
// are the comma separated positions of the parts or 0
Proc Contains
Parameters string content, part
var string results = "0"
var long posi = 1
posi = InStr(part,content,posi)
if posi <> 0
results = str$(posi)
repeat
posi = InStr(part,content,posi+1)
case posi <> 0 : results = results + "," + str$(posi)
until posi == 0
endif
Return results
EndProc
Proc StartsWith
Parameters string content, part
Return if(Left$(content,Len(part)) == part, 1, 0)
EndProc
Proc EndsWith
Parameters string content, part
Return if(Right$(content,Len(part)) == part, 1, 0)
'Return if(Left$(content,Len(content)-Len(part)+1) == part, 1, 0)
EndProc
var string theContent = "foobar"
var string thePart = "foo"
Print "Starts with: "
Print " ("+thePart+" in "+theContent+") "+if(StartsWith(theContent,thePart),"Yes","No")
thePart = "back"
Print " ("+thePart+" in "+theContent+") "+if(StartsWith(theContent,thePart),"Yes","No")
theContent = "foooooobar"
Print "Contains: "
Print " ("+thePart+" in "+theContent+") "+ Contains(theContent,thePart)
thePart = "o"
Print " ("+thePart+" in "+theContent+") "+ Contains(theContent,thePart)
theContent = "foobar"
thePart = "back"
Print "Ends with: "
Print " ("+thePart+" in "+theContent+") "+if(EndsWith(theContent,thePart),"Yes","No")
thePart = "bar"
Print " ("+thePart+" in "+theContent+") "+if(EndsWith(theContent,thePart),"Yes","No")
waitkey
end- Output:
Starts with: (foo in foobar) Yes (back in foobar) No Contains: (back in foooooobar) 0 (o in foooooobar) 2,3,4,5,6,7 Ends with: (back in foobar) No (bar in foobar) Yes
Yabasic
cadena1$ = "qwertyuiop"
//Determinar si la primera cadena comienza con la segunda cadena
cadena2$ = "qwerty"
if left$(cadena1$, len(cadena2$)) = cadena2$ then
print "'", cadena1$, "' comienza con '", cadena2$, "'"
else
print "'", cadena1$, "' no comienza con '", cadena2$, "'"
end if
//Determinar si la primera cadena contiene la segunda cadena en cualquier
//ubicación imprima la ubicación de la coincidencia para la parte 2
cadena2$ = "wert"
posic = instr(cadena1$, cadena2$)
if posic then
print "'", cadena1$, "' contiene '", cadena2$, "' en la posicion ", posic
else
print "'", cadena1$, "' no contiene '", cadena2$, "'"
end if
//Determinar si la primera cadena termina con la segunda cadena
cadena2$ = "random garbage"
if right$(cadena1$, len(cadena2$)) = cadena2$ then
print "'", cadena1$, "' termina con '", cadena2$, "'"
else
print "'", cadena1$, "' no termina con '", cadena2$, "'"
end if
end- Output:
'qwertyuiop' comienza con 'qwerty' 'qwertyuiop' contiene 'wert' en la posicion 2 'qwertyuiop' no termina con 'random garbage'
Z80 Assembly
InString:
;input: hl = pointer to string 1
; de = pointer to string 2
; assumes len(hl) <= len(de)
; output in BC
;clobbers: ix
push de
pop ix ;back up de into ix
ld bc,0 ;our return value
InString_again:
ld a,(hl)
or a
ret z
ld a,(de)
or a
ret z
cp (hl)
jr nz,InString_noMatch
inc de
jr InString_overhead
InString_noMatch:
push ix
pop de
inc bc
InString_overhead:
inc hl
jr InString_again- Output:
org &1000
ld hl,TestString
ld de,Test1 ;recompiled with each test string and tested it
call InString
ld a,c
call ShowHex
ret
TestString:
db "abcdefg",0
Test1:
db "abc",0 ;returns 0
Test2:
db "def",0 ;returns 3
Test3:
db "efg",0 ;returns 4
Test4:
db "z",0 ;returns 7zkl
fcn f(text,p){ if(text.find(p)==0)println("Yep") else println("Nope") }
f("foobar","foo") //--> Yep
f("foobar","bar") //--> Nopefcn f(text,p){ if(Void!=(n:=text.find(p)))println("Contained @",n) else println("Nope") }
f("foobar","ob") //--> Contained @2
f("foobar","food") //--> Nopefcn f(text,p){
if( Void!=(n:=text.rfind(p)) and n+p.len()==text.len() )
println("tail gunner") else println("Nope")
}
f("foobar","r"); f("foobar","ar"); //--> tail gunners
f("foobar","ob"); //--> Nope
f("foobarfoobar","bar"); //--> tail gunnerCategories:
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