Split a character string based on change of character: Difference between revisions
Split a character string based on change of character (view source)
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[[Category: String manipulation]]
[[Category:Strings]]
[[Category:Simple]]
{{
<!-- this problem is also known as "splitsville" elsewhere. !-->
<!-- I imagine this Rosetta Code task will lead to quite a few code-golf solutions. !-->
Line 22 ⟶ 24:
<big><big> g, HHH, 5, YY, ++, ///, \ </big></big>
{{Template:Strings}}
<br><br>
=={{header|11l}}==
{{trans|C++}}
<syntaxhighlight lang="11l">F split(input, delim)
V res = ‘’
L(ch) input
I !res.empty & ch != res.last
res ‘’= delim
res ‘’= ch
R res
print(split(‘gHHH5YY++///\’, ‘, ’))</syntaxhighlight>
{{out}}
<pre>
g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|8080 Assembly}}==
<syntaxhighlight lang="8080asm"> org 100h
jmp demo
;;; Split the string under DE on changing characters,
;;; and store the result at HL.
split: ldax d ; Load character from string
spcopy: mov m,a ; Store in output
cpi '$' ; CP/M string terminator
rz ; Stop when the end is reached
mov b,a ; Store previous character in B
inx d ; Increment input pointer
inx h ; Increment output pointer
ldax d ; Get next character
cmp b ; Same as previous character?
jz spcopy ; Then just copy it
cpi '$' ; Otherwise, if it is the en
jz spcopy ; Then just copy it as well
mvi m,',' ; Otherwise, add a comma and a space
inx h
mvi m,' '
inx h
jmp spcopy
;;; Demo code
demo: lxi d,string
lxi h,out
call split ; Split the string
lxi d,out
mvi c,9 ; And print it using CP/M
jmp 5
string: db 'gHHH5YY++///',5Ch,'$'
out: equ $</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|8086 Assembly}}==
<syntaxhighlight lang="asm"> cpu 8086
org 100h
section .text
jmp demo
;;; Split the string at DS:SI on changing characters,
;;; and store the result at ES:DI.
split: lodsb ; Load character
.copy: stosb ; Store in output
cmp al,'$' ; Done yet?
je .out ; If so, stop.
mov ah,al ; Store previous character
lodsb ; Get next character
cmp al,ah ; Same character?
je .copy ; Then just copy it
cmp al,'$' ; End of string?
je .copy ; Then just copy it too
mov dl,al
mov ax,', ' ; Otherwise, add a comma and a space
stosw
mov al,dl
jmp .copy
.out: ret
;;; Demo code
demo: mov si,string
mov di,buf
call split ; Split the string
mov dx,buf
mov ah,9
int 21h ; And print the result using DOS
ret
section .data
string: db 'gHHH5YY++///\$'
section .bss
buf: resb 32</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|AArch64 Assembly}}==
{{works with|as|Raspberry Pi 3B version Buster 64 bits}}
<syntaxhighlight lang="aarch64 assembly">
/* ARM assembly AARCH64 Raspberry PI 3B */
/* program splitcar64.s */
/*******************************************/
/* Constantes file */
/*******************************************/
/* for this file see task include a file in language AArch64 assembly*/
.include "../includeConstantesARM64.inc"
/*********************************/
/* Initialized data */
/*********************************/
.data
szCarriageReturn: .asciz "\n"
szString1: .asciz "gHHH5YY++///\\"
/* IMPORTANT REMARK for compiler as
The way to get special characters into a string is to escape these characters: precede them
with a backslash ‘\’ character. For example ‘\\’ represents one backslash: the first \ is
an escape which tells as to interpret the second character literally as a backslash (which
prevents as from recognizing the second \ as an escape character).
*/
/*********************************/
/* UnInitialized data */
/*********************************/
.bss
sBuffer: .skip 100
/*********************************/
/* code section */
/*********************************/
.text
.global main
main: // entry of program
ldr x0,qAdrszString1 // input string address
ldr x1,qAdrsBuffer // output buffer address
bl split
ldr x0,qAdrsBuffer
bl affichageMess // display message
ldr x0,qAdrszCarriageReturn
bl affichageMess
100: // standard end of the program
mov x0,0 // return code
mov x8,EXIT // request to exit program
svc 0 // perform the system call
qAdrszString1: .quad szString1
qAdrszCarriageReturn: .quad szCarriageReturn
qAdrsBuffer: .quad sBuffer
/******************************************************************/
/* generate value */
/******************************************************************/
/* x0 contains the address of input string */
/* x1 contains the address of output buffer */
split:
stp x1,lr,[sp,-16]! // save registers
mov x4,0 // indice loop input string
mov x5,0 // indice buffer
ldrb w2,[x0,x4] // read first char in reg x2
cbz x2,4f // if null -> end
strb w2,[x1,x5] // store char in buffer
add x5,x5,1 // increment location buffer
1:
ldrb w3,[x0,x4] //read char[x4] in reg x3
cbz x3,4f // if null end
cmp x2,x3 // compare two characters
bne 2f
strb w3,[x1,x5] // = -> store char in buffer
b 3f // loop
2:
mov x2,',' // else store comma in buffer
strb w2,[x1,x5] // store char in buffer
add x5,x5,1
mov x2,' ' // and store space in buffer
strb w2,[x1,x5]
add x5,x5,1
strb w3,[x1,x5] // and store input char in buffer
mov x2,x3 // and maj x2 with new char
3:
add x5,x5,1 // increment indices
add x4,x4,1
b 1b // and loop
4:
strb w3,[x1,x5] // store zero final in buffer
100:
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"
</syntaxhighlight>
{{Output}}<pre> gg, HHH, 5, YY, ++, ///, \ </pre>
=={{header|Action!}}==
<syntaxhighlight lang="action!">PROC Split(CHAR ARRAY s)
BYTE i
CHAR curr,last
i=1 last=s(1)
Put('")
WHILE i<=s(0)
DO
curr=s(i)
IF curr#last THEN
Print(", ")
FI
Put(curr)
last=curr
i==+1
OD
Put('")
RETURN
PROC Test(CHAR ARRAY s)
PrintF("Input: ""%S""%E",s)
Print("Split: ") Split(s)
PutE() PutE()
RETURN
PROC Main()
Test("gHHH5YY++///\")
Test("gHHH 5++,,,///\")
RETURN</syntaxhighlight>
{{out}}
[https://gitlab.com/amarok8bit/action-rosetta-code/-/raw/master/images/Split_a_character_string_based_on_change_of_character.png Screenshot from Atari 8-bit computer]
<pre>
Input: "gHHH5YY++///\"
Split: "g, HHH, 5, YY, ++, ///, \"
Input: "gHHH 5++,,,///\"
Split: "g, HHH, , 5, ++, ,,,, ///, \"
</pre>
=={{header|Ada}}==
<syntaxhighlight lang="ada">
with Ada.Text_IO;
procedure Split is
procedure Print_Tokens (s : String) is
i, j : Integer := s'First;
begin
loop
while j<=s'Last and then s(j)=s(i) loop j := j + 1; end loop;
if i/=s'first then Ada.Text_IO.Put (", "); end if;
Ada.Text_IO.Put (s(i..j-1));
i := j;
exit when j>s'last;
end loop;
end Print_Tokens;
begin
Print_Tokens ("gHHH5YY+++");
end split;
</syntaxhighlight>
=={{header|ALGOL 68}}==
<syntaxhighlight lang="algol68">BEGIN
# returns s with ", " added between each change of character #
PROC split on characters = ( STRING s )STRING:
IF s = "" THEN
# empty string #
""
ELSE
# allow for 3 times as many characters as in the string #
# this would handle a string of unique characters #
[ 3 * ( ( UPB s - LWB s ) + 1 ) ]CHAR result;
INT r pos := LWB result;
CHAR s char := s[ LWB s ];
FOR s pos FROM LWB s TO UPB s DO
IF s char /= s[ s pos ] THEN
# change of character - insert ", " #
result[ r pos ] := ",";
result[ r pos + 1 ] := " ";
r pos +:= 2;
s char := s[ s pos ]
FI;
result[ r pos ] := s[ s pos ];
r pos +:= 1
OD;
# return the used portion of the result #
result[ 1 : r pos - 1 ]
FI ; # split on characters #
print( ( split on characters( "gHHH5YY++///\" ), newline ) )
END</syntaxhighlight>
{{out}}
<pre>
g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|Amazing Hopper}}==
VERSION 1: string
<syntaxhighlight lang="c">
#include <basico.h>
#define INICIO 1
#define CHARS "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789\"+-/ \\:,;:_*"
algoritmo
objetivo = "gHHH5YY\"\"++ ///,,,\\", indice=0
largo=0, sublargo=0, v=0
#( largo = len(indice:=(onechar(CHARS,objetivo))) )
t=0, nuevo=""
para cada caracter ( v, indice, largo )
#(t = replicate(v, sublargo := ((poschar(INICIO, v, objetivo) - 1 ) ) ))
#(nuevo = cat( cat(nuevo, t), ", "))
objetivo+=sublargo
siguiente
nuevo -= 2
imprimir( "NEW STRING=\n", nuevo,NL)
terminar
</syntaxhighlight>
{{out}}
<pre>
$ hopper3 basica/splitrep.bas
NEW STRING=
g, HHH, 5, YY, "", ++, , ///, ,,,, \
</pre>
VERSION 2: arrays
<syntaxhighlight lang="c">
#include <basico.h>
#define INICIO 1
#define CHARS "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789\"+-/ \\:,;:_*"
algoritmo
objetivo = "gHHH5YY\"\"++ ///,,,,\\", indice=0
largo=0, sublargo=0, lista={}, v=0
#( largo = len(indice:=(onechar(CHARS,objetivo))) )
para cada caracter ( v, indice, largo )
#( replicate(v, sublargo := ((poschar(INICIO, v, objetivo) - 1 ))))
meter en( lista )
objetivo+=sublargo
siguiente
imprimir( "LISTA=\n", lista, NL )
terminar
</syntaxhighlight>
{{out}}
<pre>
$ hopper3 basica/splitrep2.bas
LISTA=
g,HHH,5,YY,"",++, ,///,,,,,,\
</pre>
=={{header|ANSI BASIC}}==
{{works with|Decimal BASIC}}
<syntaxhighlight lang="basic">REM >split
DECLARE EXTERNAL FUNCTION FN_split$
PRINT FN_split$( "gHHH5YY++///\" )
END
EXTERNAL FUNCTION FN_split$( s$ )
LET c$ = s$(1:1)
LET split$ = ""
FOR i = 1 TO LEN(s$)
LET d$ = s$(i:i)
IF d$ <> c$ THEN
LET split$ = split$ & ", "
LET c$ = d$
END IF
LET split$ = split$ & d$
NEXT i
LET FN_split$ = split$
END FUNCTION</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|APL}}==
{{works with|Dyalog APL}}
<syntaxhighlight lang="apl">split ← 2↓∘∊(⊂', '),¨(⊢≠¯1⌽⊢)⊂⊢</syntaxhighlight>
{{out}}
<pre> split 'gHHH5YY++///\'
g, HHH, 5, YY, ++, ///, \</pre>
=={{header|AppleScript}}==
===Functional===
{{Trans|JavaScript}}
<syntaxhighlight lang="applescript">intercalate(", ", ¬
map(curry(intercalate)'s |λ|(""), ¬
group("gHHH5YY++///\\")))
--> "g, HHH, 5, YY, ++, ///, \\"
-- GENERIC FUNCTIONS ----------------------------------------------------------
-- curry :: (Script|Handler) -> Script
on curry(f)
script
on |λ|(a)
script
on |λ|(b)
|λ|(a, b) of mReturn(f)
end |λ|
end script
end |λ|
end script
end curry
-- foldl :: (a -> b -> a) -> a -> [b] -> a
on foldl(f, startValue, xs)
tell mReturn(f)
set v to startValue
set lng to length of xs
repeat with i from 1 to lng
set v to |λ|(v, item i of xs, i, xs)
end repeat
return v
end tell
end foldl
-- group :: Eq a => [a] -> [[a]]
on group(xs)
script eq
on |λ|(a, b)
a = b
end |λ|
end script
groupBy(eq, xs)
end group
-- groupBy :: (a -> a -> Bool) -> [a] -> [[a]]
on groupBy(f, xs)
set mf to mReturn(f)
script enGroup
on |λ|(a, x)
if length of (active of a) > 0 then
set h to item 1 of active of a
else
set h to missing value
end if
if h is not missing value and mf's |λ|(h, x) then
{active:(active of a) & x, sofar:sofar of a}
else
{active:{x}, sofar:(sofar of a) & {active of a}}
end if
end |λ|
end script
if length of xs > 0 then
tell foldl(enGroup, {active:{item 1 of xs}, sofar:{}}, tail(xs))
if length of (its active) > 0 then
its sofar & its active
else
{}
end if
end tell
else
{}
end if
end groupBy
-- intercalate :: Text -> [Text] -> Text
on intercalate(strText, lstText)
set {dlm, my text item delimiters} to {my text item delimiters, strText}
set strJoined to lstText as text
set my text item delimiters to dlm
return strJoined
end intercalate
-- map :: (a -> b) -> [a] -> [b]
on map(f, xs)
tell mReturn(f)
set lng to length of xs
set lst to {}
repeat with i from 1 to lng
set end of lst to |λ|(item i of xs, i, xs)
end repeat
return lst
end tell
end map
-- Lift 2nd class handler function into 1st class script wrapper
-- mReturn :: Handler -> Script
on mReturn(f)
if class of f is script then
f
else
script
property |λ| : f
end script
end if
end mReturn
-- tail :: [a] -> [a]
on tail(xs)
if length of xs > 1 then
items 2 thru -1 of xs
else
{}
end if
end tail</syntaxhighlight>
{{Out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
===Straightforward===
(Also case-sensitve.)
<syntaxhighlight lang="applescript">on splitAtCharacterChanges(input)
set len to (count input)
if (len < 2) then return input
set chrs to input's characters
set currentChr to beginning of chrs
considering case
repeat with i from 2 to len
set thisChr to item i of chrs
if (thisChr is not currentChr) then
set item i of chrs to ", " & thisChr
set currentChr to thisChr
end if
end repeat
end considering
set astid to AppleScript's text item delimiters
set AppleScript's text item delimiters to ""
set output to chrs as text
set AppleScript's text item delimiters to astid
return output
end splitAtCharacterChanges
-- Test code:
splitAtCharacterChanges("gHHH5YY++///\\")</syntaxhighlight>
{{output}}
<syntaxhighlight lang="applescript">"g, HHH, 5, YY, ++, ///, \\"</syntaxhighlight>
===ASObjC===
<syntaxhighlight lang="applescript">use AppleScript version "2.4" -- OS X 10.10 (Yosemite) or later
use framework "Foundation"
on splitAtCharacterChanges(input)
tell (current application's class "NSMutableString"'s stringWithString:(input)) to ¬
return (its stringByReplacingOccurrencesOfString:("(.)\\1*+(?!$)") withString:("$0, ") ¬
options:(current application's NSRegularExpressionSearch) range:({0, its |length|()})) as text
end splitAtCharacterChanges
-- Test code:
splitAtCharacterChanges("gHHH5YY++///\\")</syntaxhighlight>
{{output}}
<syntaxhighlight lang="applescript">"g, HHH, 5, YY, ++, ///, \\"</syntaxhighlight>
=={{header|ARM Assembly}}==
{{works with|as|Raspberry Pi}}
<syntaxhighlight lang="arm assembly">
/* ARM assembly Raspberry PI */
/* program splitcar.s */
/************************************/
/* Constantes */
/************************************/
.equ STDOUT, 1 @ Linux output console
.equ EXIT, 1 @ Linux syscall
.equ WRITE, 4 @ Linux syscall
/*********************************/
/* Initialized data */
/*********************************/
.data
szCarriageReturn: .asciz "\n"
szString1: .asciz "gHHH5YY++///\\"
/* IMPORTANT REMARK for compiler as
The way to get special characters into a string is to escape these characters: precede them
with a backslash ‘\’ character. For example ‘\\’ represents one backslash: the first \ is
an escape which tells as to interpret the second character literally as a backslash (which
prevents as from recognizing the second \ as an escape character).
*/
/*********************************/
/* UnInitialized data */
/*********************************/
.bss
sBuffer: .skip 100
/*********************************/
/* code section */
/*********************************/
.text
.global main
main: @ entry of program
ldr r0,iAdrszString1 @ input string address
ldr r1,iAdrsBuffer @ output buffer address
bl split
ldr r0,iAdrsBuffer
bl affichageMess @ display message
ldr r0,iAdrszCarriageReturn
bl affichageMess
100: @ standard end of the program
mov r0, #0 @ return code
mov r7, #EXIT @ request to exit program
svc #0 @ perform the system call
iAdrszString1: .int szString1
iAdrszCarriageReturn: .int szCarriageReturn
iAdrsBuffer: .int sBuffer
/******************************************************************/
/* generate value */
/******************************************************************/
/* r0 contains the address of input string */
/* r1 contains the address of output buffer */
split:
push {r1-r5,lr} @ save registers
mov r4,#0 @ indice loop input string
mov r5,#0 @ indice buffer
ldrb r2,[r0,r4] @ read first char in reg r2
cmp r2,#0 @ if null -> end
beq 3f
strb r2,[r1,r5] @ store char in buffer
add r5,#1 @ increment location buffer
1:
ldrb r3,[r0,r4] @read char[r4] in reg r3
cmp r3,#0 @ if null end
beq 3f
cmp r2,r3 @ compare two characters
streqb r3,[r1,r5] @ = -> store char in buffer
beq 2f @ loop
mov r2,#',' @ else store comma in buffer
strb r2,[r1,r5] @ store char in buffer
add r5,#1
mov r2,#' ' @ and store space in buffer
strb r2,[r1,r5]
add r5,#1
strb r3,[r1,r5] @ and store input char in buffer
mov r2,r3 @ and maj r2 with new char
2:
add r5,#1 @ increment indices
add r4,#1
b 1b @ and loop
3:
strb r3,[r1,r5] @ store zero final in buffer
100:
pop {r1-r5,lr}
bx lr @ return
/******************************************************************/
/* display text with size calculation */
/******************************************************************/
/* r0 contains the address of the message */
affichageMess:
push {r0,r1,r2,r7,lr} @ save registres
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 systeme
pop {r0,r1,r2,r7,lr} @ restaur des 2 registres */
bx lr @ return
output : gg, HHH, 5, YY, ++, ///, \
</syntaxhighlight>
=={{header|Arturo}}==
<syntaxhighlight lang="rebol">parts: [] current: ""
loop split {gHHH5YY++///\} 'ch [
if? or? empty? current
contains? current ch -> 'current ++ ch
else [
'parts ++ current
current: new ch
]
]
'parts ++ current
print parts</syntaxhighlight>
{{out}}
<pre>g HHH 5 YY ++ /// \</pre>
=={{header|AutoHotkey}}==
<syntaxhighlight lang="autohotkey">Split_Change(str){
for i, v in StrSplit(str)
res .= (v=prev) ? v : (res?", " :"") v , prev := v
return res
}</syntaxhighlight>
Examples:<syntaxhighlight lang="autohotkey">str := "gHHH5YY++///\"
MsgBox % Split_Change(str)</syntaxhighlight>
Outputs:<pre>g, HHH, 5, YY, ++, ///, \</pre>
===RegEx Version===
<syntaxhighlight lang="autohotkey">Split_Change(str){
return RegExReplace(str, "(.)\1*(?!$)", "$0, ")
}</syntaxhighlight>
Examples:<syntaxhighlight lang="autohotkey">str := "gHHH5YY++///\"
MsgBox % Split_Change(str)</syntaxhighlight>
Outputs:<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|AWK}}==
<syntaxhighlight lang="awk">
# syntax: GAWK -f SPLIT_A_CHARACTER_STRING_BASED_ON_CHANGE_OF_CHARACTER.AWK
BEGIN {
str = "gHHH5YY++///\\"
printf("old: %s\n",str)
printf("new: %s\n",split_on_change(str))
exit(0)
}
function split_on_change(str, c,i,new_str) {
new_str = substr(str,1,1)
for (i=2; i<=length(str); i++) {
c = substr(str,i,1)
if (substr(str,i-1,1) != c) {
new_str = new_str ", "
}
new_str = new_str c
}
return(new_str)
}
</syntaxhighlight>
{{out}}
<pre>
old: gHHH5YY++///\
new: g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|BaCon}}==
Literal strings in BaCon are passed to the C compiler as they are; a backslash therefore needs to be escaped.
<syntaxhighlight lang="freebasic">txt$ = "gHHH5YY++///\\"
c$ = LEFT$(txt$, 1)
FOR x = 1 TO LEN(txt$)
d$ = MID$(txt$, x, 1)
IF d$ <> c$ THEN
PRINT ", ";
c$ = d$
END IF
PRINT d$;
NEXT</syntaxhighlight>
{{out}}
<pre>
g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|BASIC256}}==
<syntaxhighlight lang="freebasic">function split$(instring$)
if length(instring$) < 2 then return instring$
ret$ = left(instring$,1)
for i = 2 to length(instring$)
if mid(instring$,i,1) <> mid(instring$, i-1, 1) then ret$ += ", "
ret$ += mid(instring$, i, 1)
next i
return ret$
end function
print split$("gHHH5YY++///\")</syntaxhighlight>
=={{header|BBC BASIC}}==
<syntaxhighlight lang="bbcbasic">REM >split
PRINT FN_split( "gHHH5YY++///\" )
END
DEF FN_split( s$ )
LOCAL c$, split$, d$, i%
c$ = LEFT$( s$, 1 )
split$ = ""
FOR i% = 1 TO LEN s$
LET d$ = MID$( s$, i%, 1 )
IF d$ <> c$ THEN
split$ += ", "
c$ = d$
ENDIF
split$ += d$
NEXT
= split$</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|BQN}}==
<syntaxhighlight lang="bqn">Split ← (+`⊏⊸»⊸≠)⊸⊔
Join ← {∾⟜𝕨⊸∾´𝕩}
", " Join⟜Split "gHHH5YY++///\"</syntaxhighlight>
{{out}}
<pre>"g, HHH, 5, YY, ++, ///, \"</pre>
=={{header|C}}==
<syntaxhighlight lang="c">#include <stdio.h>
#include <stdlib.h>
#include <string.h>
char *split(char *str);
int main(int argc,char **argv)
{
char input[13]="gHHH5YY++///\\";
printf("%s\n",split(input));
}
char *split(char *str)
{
char last=*str,*result=malloc(3*strlen(str)),*counter=result;
for (char *c=str;*c;c++) {
if (*c!=last) {
strcpy(counter,", ");
counter+=2;
last=*c;
}
*counter=*c;
counter++;
}
*(counter--)='\0';
return realloc(result,strlen(result));
}</syntaxhighlight>
{{out}}
<pre>
g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|C sharp}}==
<syntaxhighlight lang="csharp">using System;
using System.Linq;
using System.Collections.Generic;
public class Program
{
string s = @"gHHH5YY++///\";
Console.WriteLine(s.RunLengthSplit().Delimit(", "));
}
public static class Extensions
{
public static IEnumerable<string> RunLengthSplit(this string source) {
using (var enumerator = source.GetEnumerator()) {
if (!enumerator.MoveNext()) yield break;
char previous = enumerator.Current;
int count = 1;
while (enumerator.MoveNext()) {
if (previous == enumerator.Current) {
count++;
} else {
yield return new string(Enumerable.Repeat(previous, count).ToArray());
previous = enumerator.Current;
count = 1;
}
}
yield return new string(Enumerable.Repeat(previous, count).ToArray());
}
}
public static string Delimit<T>(this IEnumerable<T> source, string separator = "") => string.Join(separator ?? "", source);
}</syntaxhighlight>
{{out}}
<pre>
g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|C++}}==
<syntaxhighlight lang="cpp">
// Solution for http://rosettacode.org/wiki/Split_a_character_string_based_on_change_of_character
#include<string>
#include<iostream>
auto split(const std::string& input, const std::string& delim){
std::string res;
for(auto ch : input){
if(!res.empty() && ch != res.back())
res += delim;
res += ch;
}
return res;
}
int main(){
std::cout << split("gHHH5 ))YY++,,,///\\", ", ") << std::endl;
}</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, , )), YY, ++, ,,,, ///, \</pre>
=={{header|Clojure}}==
<syntaxhighlight lang="clojure">(defn print-cchanges [s]
(println (clojure.string/join ", " (map first (re-seq #"(.)\1*" s)))))
(print-cchanges "gHHH5YY++///\\")
</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|CLU}}==
<syntaxhighlight lang="clu">% Split a string based on a change of character
split_on_change = iter (s: string) yields (string)
part: string := ""
for c: char in string$chars(s) do
if ~string$empty(part)
cand part[string$size(part)] ~= c then
yield(part)
part := ""
end
part := part || string$c2s(c)
end
yield(part)
end split_on_change
start_up = proc ()
po: stream := stream$primary_output()
str: string := "gHHH5YYY++///\\" % \\ escapes, as in C
rslt: string := ""
first: bool := true
for part: string in split_on_change(str) do
if first then first := false
else rslt := rslt || ", "
end
rslt := rslt || part
end
stream$putl(po, rslt)
end start_up</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YYY, ++, ///, \</pre>
=={{header|COBOL}}==
<syntaxhighlight lang="cobol">
identification division.
program-id. split-ch.
data division.
1 split-str pic x(30) value space.
88 str-1 value "gHHH5YY++///\".
88 str-2 value "gHHH5 ))YY++,,,///\".
1 binary.
2 ptr pic 9(4) value 1.
2 str-start pic 9(4) value 1.
2 delim-len pic 9(4) value 1.
2 split-str-len pic 9(4) value 0.
2 trash-9 pic 9(4) value 0.
1 delim-char pic x value space.
1 delim-str pic x(6) value space.
1 trash-x pic x.
procedure division.
display "Requested string"
set str-1 to true
perform split-init-and-go
display space
display "With spaces and commas"
set str-2 to true
perform split-init-and-go
stop run
.
split-init-and-go.
move 1 to ptr
move 0 to split-str-len
perform split
.
split.
perform get-split-str-len
display split-str (1:split-str-len)
perform until ptr > split-str-len
move ptr to str-start
move split-str (ptr:1) to delim-char
unstring split-str (1:split-str-len)
delimited all delim-char
into trash-x delimiter delim-str
pointer ptr
end-unstring
subtract str-start from ptr giving delim-len
move split-str (str-start:delim-len)
to delim-str (1:delim-len)
display delim-str (1:delim-len) with no advancing
if ptr <= split-str-len
display ", " with no advancing
end-if
end-perform
display space
.
get-split-str-len.
inspect function reverse (split-str) tallying
trash-9 for leading space
split-str-len for characters after space
.
end program split-ch.
</syntaxhighlight>
{{out}}
<pre>
Requested string
gHHH5YY++///\
g, HHH, 5, YY, ++, ///, \
With spaces and commas
gHHH5 ))YY++,,,///\
g, HHH, 5, , )), YY, ++, ,,,, ///, \
</pre>
=={{header|Common Lisp}}==
<syntaxhighlight lang="lisp">(defun split (string)
(loop :for prev := nil :then c
:for c :across string
:do (format t "~:[~;, ~]~c" (and prev (char/= c prev)) c)))
(split "gHHH5YY++///\\")
</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
Doing more work that what's being ask, the following solution builds a list of strings then output it:
<syntaxhighlight lang="lisp">(defun split (string)
(flet ((make-buffer ()
(make-array 0 :element-type 'character :adjustable t :fill-pointer t)))
(loop with buffer = (make-buffer)
with result
for prev = nil then c
for c across string
when (and prev (char/= c prev))
do (push buffer result)
(setf buffer (make-buffer))
do (vector-push-extend c buffer)
finally (push buffer result)
(format t "~{~A~^, ~}"(nreverse result)))))
(split "gHHH5YY++///\\")</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|Cowgol}}==
<syntaxhighlight lang="cowgol">include "cowgol.coh";
sub split(in: [uint8], buf: [uint8]): (out: [uint8]) is
out := buf;
loop
[buf] := [in];
if [in] == 0 then break; end if;
if [in] != [@next in] and [@next in] != 0 then
[buf+1] := ',';
[buf+2] := ' ';
buf := buf+2;
end if;
buf := buf+1;
in := in+1;
end loop;
end sub;
var buf: uint8[32];
print(split("gHHH5YY++//\\", &buf[0]));
print_nl();</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, //, \</pre>
=={{header|D}}==
<syntaxhighlight lang="d">import std.stdio;
void main() {
auto source = "gHHH5YY++///\\";
char prev = source[0];
foreach(ch; source) {
if (prev != ch) {
prev = ch;
write(", ");
}
write(ch);
}
writeln();
}</syntaxhighlight>
{{output}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|Delphi}}==
{{works with|Delphi|6.0}}
{{libheader|SysUtils,StdCtrls}}
<syntaxhighlight lang="Delphi">
function SplitStringCharChange(S: string): string;
{Split string whenever the previous char is different from the current one}
var I: integer;
var C: char;
begin
Result:='';
{Copy string to output}
for I:=1 to Length(S) do
begin
Result:=Result+S[I];
{Appended ", " if the next char is different}
if (I<Length(S)) and (S[I]<>S[I+1]) then Result:=Result+', ';
end;
end;
procedure ShowSplitString(Memo: TMemo);
const S1 = 'gHHH5YY++///\';
var S2: string;
begin
Memo.Lines.Add(S1);
S2:=SplitStringCharChange(S1);
Memo.Lines.Add(S2);
end;
</syntaxhighlight>
{{out}}
<pre>
gHHH5YY++///\
g, HHH, 5, YY, ++, ///, \
Elapsed Time: 1.767 ms.
</pre>
=={{header|Dyalect}}==
<syntaxhighlight lang="dyalect">func String.SmartSplit() {
var c
var str = ""
var last = this.Length() - 1
for n in 0..last {
if c && this[n] != c {
str += ", "
}
c = this[n]
str += c
}
str
}
print("gHHH5YY++///\\".SmartSplit())</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|EasyLang}}==
<syntaxhighlight lang="text">
a$ = "gHHH5YY++///\\"
a$[] = strchars a$
cp$ = a$[1]
for c$ in a$[]
if c$ <> cp$
s$ &= ", "
cp$ = c$
.
s$ &= c$
.
print s$
</syntaxhighlight>
{{out}}
<pre>
g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|Elixir}}==
<syntaxhighlight lang="elixir">split = fn str ->
IO.puts " input string: #{str}"
String.graphemes(str)
|> Enum.chunk_by(&(&1))
|> Enum.map_join(", ", &Enum.join &1)
|> fn s -> IO.puts "output string: #{s}" end.()
end
split.("gHHH5YY++///\\")</syntaxhighlight>
{{out}}
<pre>
input string: gHHH5YY++///\
output string: g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|F_Sharp|F#}}==
<syntaxhighlight lang="fsharp">open System.Text.RegularExpressions
let splitRuns s = Regex("""(.)\1*""").Matches(s) |> Seq.cast<Match> |> Seq.map (fun m -> m.Value) |> Seq.toList
printfn "%A" (splitRuns """gHHH5YY++///\""")</syntaxhighlight>
{{out}}
<pre>["g"; "HHH"; "5"; "YY"; "++"; "///"; "\"]</pre>
=={{header|Factor}}==
<syntaxhighlight lang="factor">USE: splitting.monotonic
"gHHH5YY++///\\"
"aaabbccccdeeff" [ [ = ] monotonic-split ", " join print ] bi@</syntaxhighlight>
{{out}}
<pre>
g, HHH, 5, YY, ++, ///, \
aaa, bb, cccc, d, ee, ff
</pre>
=={{header|Forth}}==
{{works with|Gforth|0.7.3}}
<syntaxhighlight lang="forth">CREATE A 0 ,
: C@A+ A @ C@ [ 1 CHARS ]L A +! ;
: SPLIT. ( c-addr u --) SWAP A ! A @ C@
BEGIN OVER WHILE
C@A+ TUCK <> IF ." , " THEN
DUP EMIT SWAP 1- SWAP
REPEAT DROP ;
: TEST OVER OVER
." input: " TYPE CR
." split: " SPLIT. CR ;
s" gHHH5YY++///\" TEST
s" gHHH5 ))YY++,,,///\" TEST
BYE</syntaxhighlight>
{{out}}
<pre>input: gHHH5YY++///\
split: g, HHH, 5, YY, ++, ///, \
input: gHHH5 ))YY++,,,///\
split: g, HHH, 5, , )), YY, ++, ,,,, ///, \</pre>
=={{header|Fortran}}==
This is F77 style, except for the <code>END SUBROUTINE SPLATTER</code> which would be just <code>END</code>, which for F90 is also allowable outside of the MODULE protocol. Linking the start/stop markers by giving the same name is helpful, especially when the compiler checks for this. The $ symbol at the end of a FORMAT code sequence is a common F77 extension, meaning "do not finish the line" so that a later output will follow on. This is acceptable to F90 and is less blather than adding the term <code>,ADVANCE = "NO"</code> inside a WRITE statement that would otherwise be required. Output is to I/O unit <code>6</code> which is the modern default for "standard output". The format code is <code>A</code> meaning "any number of characters" rather than <code>A1</code> for "one character" so as to accommodate not just the single character from TEXT but also the two characters of ", " for the splitter between sequences. Alas, there is no provision to change fount or colour for this, to facilitate the reader's attempts to parse the resulting list especially when the text includes commas or spaces of its own. By contrast, with quoted strings, the standard protocol is to double contained quotes.
An alternative method would be to prepare the entire output in a CHARACTER variable then write that, but this means answering the maddening question "how long is a piece of string?" for that variable, though later Fortran has arrangements whereby a text variable is resized to suit on every assignment, as in <code>TEMP = TEMP // more</code> - but this means repeatedly copying the text to the new manifestation of the variable. Still another approach would be to prepare an array of fingers to each split point (as in [[Phrase_reversals#Fortran]]) so that the final output would be a single WRITE using that array, and again, how big must the array be? At most, as big as the number of characters in TEXT. With F90, subroutines can declare arrays of a size determined on entry, with something like <code>INTEGER A(LEN(TEXT))</code>
If the problem were to be solved by writing a "main line" only, there would have to be a declaration of the text variable there but since a subroutine can receive a CHARACTER variable of any size (the actual size is passed as a secret parameter), this can be dodged.
For this example a DO-loop stepping along the text is convenient, but in a larger context it would probably be most useful to work along the text with fingers L1 and L2 marking the start and finish positions of each sequence. <syntaxhighlight lang="fortran"> SUBROUTINE SPLATTER(TEXT) !Print a comma-separated list. Repeated characters constitute one item.
Can't display the inserted commas in a different colour so as not to look like any commas in TEXT.
CHARACTER*(*) TEXT !The text.
INTEGER L !A finger.
CHARACTER*1 C !A state follower.
IF (LEN(TEXT).LE.0) RETURN !Prevent surprises in the following..
C = TEXT(1:1) !Syncopation: what went before.
DO L = 1,LEN(TEXT) !Step through the text.
IF (C.NE.TEXT(L:L)) THEN !A change of character?
C = TEXT(L:L) !Yes. This is the new normal.
WRITE (6,1) ", " !Set off from what went before. This is not from TEXT.
END IF !So much for changes.
WRITE (6,1) C !Roll the current character. (=TEXT(L:L))
1 FORMAT (A,$) !The $ sez: do not end the line.
END DO !On to the next character.
WRITE (6,1) !Thus end the line. No output item means that the $ is not reached, so the line is ended.
END SUBROUTINE SPLATTER !TEXT with spaces, or worse, commas, will produce an odd-looking list.
PROGRAM POKE
CALL SPLATTER("gHHH5YY++///\") !The example given.
END</syntaxhighlight>
Unfortunately, the syntax highlighter has failed to notice the terminating quote character, presumably because the preceding backslash might be an "escape sequence" trigger, a facility ''not'' used in Fortran text ''literals'' except possibly as a later modernist option.
{{Out}}
<pre>
g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|FreeBASIC}}==
<syntaxhighlight lang="freebasic">function split( instring as string ) as string
if len(instring) < 2 then return instring
dim as string ret = left(instring,1)
for i as uinteger = 2 to len(instring)
if mid(instring,i,1)<>mid(instring, i - 1, 1) then ret + = ", "
ret += mid(instring, i, 1)
next i
return ret
end function</syntaxhighlight>
=={{header|Frink}}==
<syntaxhighlight lang="frink">s = "gHHH5YY++///\\"
println[join[", ", map[getFunction["first", 1], s =~ %r/((.)\2*)/g]]]</syntaxhighlight>
{{out}}
<pre>
g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|FutureBasic}}==
FB can process either Pascal strings (slowly being deprecated), or Apple's Core Foundation CFStrings (and Objective-C NSStrings). Here's the old-school Pascal string function:
<syntaxhighlight lang="text">
local fn SplitString( inputStr as Str255 ) as Str255
Str255 resultStr
NSUInteger i
if len$( inputStr ) < 2 then resultStr = inputStr : exit fn
resultStr = left$( inputStr, 1 )
for i = 2 to len$( inputStr )
if mid$( inputStr, i, 1 ) <> mid$( inputStr, i - 1, 1 ) then resultStr = resultStr + ", "
resultStr = resultStr + mid$(inputStr, i, 1)
next
end fn = resultStr
window 1
print fn SplitString( "gHHH5YY++///\" )
HandleEvents
</syntaxhighlight>
And here's the recommended CFString counterpart:
<syntaxhighlight lang="text">
local fn SplitString( inputStr as CFStringRef ) as CFStringRef
NSUInteger i
unichar chr, lastChr = fn StringCharacterAtIndex( inputStr, 0 )
CFMutableStringRef resultStr = fn MutableStringWithCapacity(0)
for i = 0 to len( inputStr ) - 1
chr = fn StringCharacterAtIndex( inputStr, i )
if ( chr != lastChr ) then MutableStringAppendString( resultStr, @", " )
MutableStringAppendString( resultStr, mid( inputStr, i, 1 ) )
lastChr = chr
next
end fn = resultStr
window 1
print fn SplitString( @"gHHH5YY++///\\" )
HandleEvents
</syntaxhighlight>
'''Output for either function:'''
<pre>
g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|Go}}==
Treating "character" as a byte:
<syntaxhighlight lang="go">package main
import (
"fmt"
"strings"
)
func main() {
fmt.Println(scc(`gHHH5YY++///\`))
}
func scc(s string) string {
if len(s) < 2 {
return s
}
var b strings.Builder
p := s[0]
b.WriteByte(p)
for _, c := range []byte(s[1:]) {
if c != p {
b.WriteString(", ")
}
b.WriteByte(c)
p = c
}
return b.String()
}</syntaxhighlight>
{{out}}
<pre>
g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|Haskell}}==
<syntaxhighlight lang="haskell">import Data.List (group, intercalate)
main :: IO ()
main = putStrLn $ intercalate ", " (group "gHHH5YY++///\\")</syntaxhighlight>
{{Out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
or as a hand-written fold:
<syntaxhighlight lang="haskell">import Data.List (intercalate)
import Data.Bool (bool)
charGroups :: String -> [String]
charGroups =
let go (a, b) (s, groups)
| a == b = (b : s, groups)
| otherwise =
( [a],
bool s [b] (null s) : groups
)
in uncurry (:) . foldr go ([], []) . (zip <*> tail)
main :: IO ()
main =
putStrLn $ intercalate ", " $ charGroups "gHHH5YY++///\\"</syntaxhighlight>
<pre>g, HHH, 5, YY, ++, ///, \</pre>
or in terms of '''span''':
<syntaxhighlight lang="haskell">import Data.List (intercalate)
charGroups :: String -> [String]
charGroups [] = []
charGroups (c : cs) =
let (xs, ys) = span (c ==) cs
in (c : xs) : charGroups ys
main :: IO ()
main =
putStrLn $ intercalate ", " $ charGroups "gHHH5YY++///\\"</syntaxhighlight>
{{Out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|IS-BASIC}}==
<syntaxhighlight lang="is-basic">100 LET S$="gHHH5YY++///\"
110 PRINT S$(1);
120 FOR I=2 TO LEN(S$)
130 IF S$(I)<>S$(I-1) THEN PRINT ", ";
140 PRINT S$(I);
150 NEXT
160 PRINT</syntaxhighlight>
=={{header|J}}==
'''Solution:'''
<syntaxhighlight lang="j">splitChars=: (1 ,~ 2 ~:/\ ]) <;.2 ]
delimitChars=: ', ' joinstring splitChars</syntaxhighlight>
'''Example Usage:'''
<syntaxhighlight lang="j"> delimitChars 'gHHH5YY++///\'
g, HHH, 5, YY, ++, ///, \</syntaxhighlight>
=={{header|Java}}==
You can use a regular expression to capture every character preceded by 0 or more of itself.
<syntaxhighlight lang="java">
import java.util.regex.Matcher;
import java.util.regex.Pattern;
</syntaxhighlight>
<syntaxhighlight lang="java">
String split(String string) {
Pattern pattern = Pattern.compile("(.)\\1*");
Matcher matcher = pattern.matcher(string);
StringBuilder strings = new StringBuilder();
int index = 0;
while (matcher.find()) {
if (index++ != 0)
strings.append(", ");
strings.append(matcher.group());
}
return strings.toString();
}
</syntaxhighlight>
<pre>
g, HHH, 5, YY, ++, ///, \
</pre>
<br />
An alternate demonstration
<syntaxhighlight lang="java">package org.rosettacode;
import java.util.ArrayList;
import java.util.List;
/**
* This class provides a main method that will, for each arg provided,
* transform a String into a list of sub-strings, where each contiguous
* series of characters is made into a String, then the next, and so on,
* and then it will output them all separated by a comma and a space.
*/
public class SplitStringByCharacterChange {
public static void main(String... args){
for (String string : args){
List<String> resultStrings = splitStringByCharacter(string);
String output = formatList(resultStrings);
System.out.println(output);
}
}
/**
* @param string String - String to split
* @return List<\String> - substrings of contiguous characters
*/
public static List<String> splitStringByCharacter(String string){
List<String> resultStrings = new ArrayList<>();
StringBuilder currentString = new StringBuilder();
for (int pointer = 0; pointer < string.length(); pointer++){
currentString.append(string.charAt(pointer));
if (pointer == string.length() - 1
|| currentString.charAt(0) != string.charAt(pointer + 1)) {
resultStrings.add(currentString.toString());
currentString = new StringBuilder();
}
}
return resultStrings;
}
/**
* @param list List<\String> - list of strings to format as a comma+space-delimited string
* @return String
*/
public static String formatList(List<String> list){
StringBuilder output = new StringBuilder();
for (int pointer = 0; pointer < list.size(); pointer++){
output.append(list.get(pointer));
if (pointer != list.size() - 1){
output.append(", ");
}
}
return output.toString();
}
}</syntaxhighlight>
{{Out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|JavaScript}}==
===ES6===
{{Trans|Haskell}}
<syntaxhighlight lang="javascript">(() => {
"use strict";
// ----------- SPLIT ON CHARACTER CHANGES ------------
const main = () =>
group("gHHH5YY++///\\")
.map(x => x.join(""))
.join(", ");
// --------------------- GENERIC ---------------------
// group :: [a] -> [[a]]
const group = xs =>
// A list of lists, each containing only
// elements equal under (===), such that the
// concatenation of these lists is xs.
groupBy(a => b => a === b)(xs);
// groupBy :: (a -> a -> Bool) [a] -> [[a]]
const groupBy = eqOp =>
// A list of lists, each containing only elements
// equal under the given equality operator,
// such that the concatenation of these lists is xs.
xs => 0 < xs.length ? (() => {
const [h, ...t] = xs;
const [groups, g] = t.reduce(
([gs, a], x) => eqOp(x)(a[0]) ? (
Tuple(gs)([...a, x])
) : Tuple([...gs, a])([x]),
Tuple([])([h])
);
return [...groups, g];
})() : [];
// Tuple (,) :: a -> b -> (a, b)
const Tuple = a =>
b => ({
type: "Tuple",
"0": a,
"1": b,
length: 2,
*[Symbol.iterator]() {
for (const k in this) {
if (!isNaN(k)) {
yield this[k];
}
}
}
});
// MAIN ---
return main();
})();</syntaxhighlight>
{{Out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
Or, in terms of a general `span` function:
<syntaxhighlight lang="javascript">(() => {
"use strict";
// -------- STRING SPLIT ON CHARACTER CHANGES --------
// charGroups :: String -> [String]
const charGroups = s =>
// The characters of s split at each point where
// consecutive characters differ.
0 < s.length ? (() => {
const
c = s[0],
[xs, ys] = span(x => c === x)([
...s.slice(1)
]);
return [
[c, ...xs], ...charGroups(ys)
]
.map(zs => [...zs].join(""));
})() : "";
// ---------------------- TEST -----------------------
// main :: IO()
const main = () =>
charGroups("gHHH5YY++///\\")
.join(", ");
// --------------------- GENERIC ---------------------
// span :: (a -> Bool) -> [a] -> ([a], [a])
const span = p =>
// Longest prefix of xs consisting of elements which
// all satisfy p, tupled with the remainder of xs.
xs => {
const i = xs.findIndex(x => !p(x));
return -1 !== i ? [
xs.slice(0, i),
xs.slice(i)
] : [xs, []];
};
// MAIN ---
return main();
})();</syntaxhighlight>
{{Out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|jq}}==
<syntaxhighlight lang="jq"># input: a string
# output: a stream of runs
def runs:
def init:
explode as $s
| $s[0] as $i
| (1 | until( $s[.] != $i; .+1));
if length == 0 then empty
elif length == 1 then .
else init as $n | .[0:$n], (.[$n:] | runs)
end;
"gHHH5YY++///\\" | [runs] | join(", ")</syntaxhighlight>
{{out}}
Using the -r ("raw output") command-line option of jq:
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|Jsish}}==
Showing off a little unit testing...
Starting with
<syntaxhighlight lang="javascript">#!/usr/bin/env jsish
;'Split a string based on change of character, in Jsish';
function splitOnChange(str:string):string {
if (str.length < 2) return str;
var last = str[0];
var result = last;
for (var pos = 1; pos < str.length; pos++) {
result += ((last == str[pos]) ? last : ', ' + str[pos]);
last = str[pos];
}
return result;
}
provide('splitOnChange', 1.0);
/* literal backslash needs escaping during initial processing */
;splitOnChange('gHHH5YY++///\\');
;splitOnChange('a');
;splitOnChange('ab');
;splitOnChange('aaa');
;splitOnChange('aaaba');
;splitOnChange('gH HH5YY++//,/\\');</syntaxhighlight>
Then
<pre>
prompt$ jsish -u -update true splitOnChange.jsi
Created splitOnChange.jsi</pre>
Giving
<syntaxhighlight lang="javascript">#!/usr/bin/env jsish
;'Split a string based on change of character, in Jsish';
function splitOnChange(str:string):string {
if (str.length < 2) return str;
var last = str[0];
var result = last;
for (var pos = 1; pos < str.length; pos++) {
(last == str[pos]) ? result += last : result += ', ' + str[pos];
last = str[pos];
}
return result;
}
provide('splitOnChange', 1.0);
/* literal backslash needs escaping during initial processing */
;splitOnChange('gHHH5YY++///\\');
;splitOnChange('a');
;splitOnChange('ab');
;splitOnChange('aaa');
;splitOnChange('aaaba');
;splitOnChange('gH HH5YY++//,/\\');
/*
=!EXPECTSTART!=
'Split a string based on change of character, in Jsish'
splitOnChange('gHHH5YY++///\') ==> g, HHH, 5, YY, ++, ///, \
splitOnChange('a') ==> a
splitOnChange('ab') ==> a, b
splitOnChange('aaa') ==> aaa
splitOnChange('aaaba') ==> aaa, b, a
splitOnChange('gH HH5YY++//,/\') ==> g, H, , HH, 5, YY, ++, //, ,, /, \
=!EXPECTEND!=
*/</syntaxhighlight>
Which tests as:
<pre>prompt$ jsish -u splitOnChange.jsi
[PASS] splitOnChange.jsi</pre>
And then satisfying the task of showing the one result, using the script as a module:
{{out}}
<pre>prompt$ jsish
Jsish interactive: see 'help [cmd]'. \ cancels > input. ctrl-c aborts running script.
# require('splitOnChange');
1
# puts(splitOnChange('gHHH5YY++///\\'));
g, HHH, 5, YY, ++, ///, \</pre>
=={{header|Julia}}==
<syntaxhighlight lang="julia"># v0.6
using IterTools
str = "gHHH5YY++///\\"
sep = map(join, groupby(identity, str))
println("string: $str\nseparated: ", join(sep, ", "))</syntaxhighlight>
{{out}}
<pre>string: gHHH5YY++///\
separated: g, HHH, 5, YY, ++, ///, \</pre>
=={{header|K}}==
<syntaxhighlight lang="k">split: {(&~=':x)_x}
","/ split "gHHH5YY++///\\"</syntaxhighlight>
{{out}}
<pre>"g,HHH,5,YY,++,///,\\"</pre>
=={{header|Kotlin}}==
<syntaxhighlight lang="kotlin">// version 1.0.6
fun splitOnChange(s: String): String {
if (s.length < 2) return s
var t = s.take(1)
for (i in 1 until s.length)
if (t.last() == s[i]) t += s[i]
else t += ", " + s[i]
return t
}
fun main(args: Array<String>) {
val s = """gHHH5YY++///\"""
println(splitOnChange(s))
}</syntaxhighlight>
{{out}}
<pre>
g, HHH, 5, YY, ++, ///, \
</pre>
=== Using fold() ===
<syntaxhighlight lang="kotlin">
fun splitOnChange(src: String): String =
src.fold("") { acc, c ->
if (acc.isEmpty() || acc.last() == c) "$acc$c" else "$acc, $c"
}
fun main() {
splitOnChange("""gHHH5YY++///\""").also { println(it)}
}
</syntaxhighlight>
{{out}}
<pre>
g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|Lambdatalk}}==
<syntaxhighlight lang="scheme">
{def mysplit
{def mysplit.r
{lambda {:w :i}
{if {> :i {W.length :w}}
then
else {if {not {W.equal? {W.get :i :w} {W.get {+ :i 1} :w}}}
then ____ else} {W.get {+ :i 1} :w}{mysplit.r :w {+ :i 1}}}}}
{lambda {:w}
{S.replace ____ by in {mysplit.r #:w 0}}}}
-> mysplit
{mysplit gHHH5YY++///\}
-> g HHH 5 YY ++ /// \
</syntaxhighlight>
=={{header|Lua}}==
Note that the backslash must be quoted as a double backslash as Lua uses C-like escape sequences.
<syntaxhighlight lang="lua">function charSplit (inStr)
local outStr, nextChar = inStr:sub(1, 1)
for pos = 2, #inStr do
nextChar = inStr:sub(pos, pos)
if nextChar ~= outStr:sub(#outStr, #outStr) then
outStr = outStr .. ", "
end
outStr = outStr .. nextChar
end
return outStr
end
print(charSplit("gHHH5YY++///\\"))</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
'''Alternative:'''
Simply scan difference in reverse order and insert delimiter in place, the loop counter i will not update with length of s.
<syntaxhighlight lang="lua">function splitdiff(s)
for i=#s,2,-1 do
if s:sub(i,i)~=s:sub(i-1,i-1) then
s = s:sub(1,i-1)..', '.. s:sub(i,-1)
end
end
return s
end</syntaxhighlight>
=={{header|Ksh}}==
<syntaxhighlight lang="ksh">
#!/bin/ksh
# Split a character string based on change of character
# # Variables:
#
str='gHHH5YY++///\'
delim=', '
# # Functions:
#
# # Function _splitonchg(str, delim) - return str split by delim at char change
#
function _splitonchg {
typeset _str ; _str="$1"
typeset _delim ; _delim="$2"
typeset _i _splitstr ; integer _i
for ((_i=1; _i<${#_str}+1; _i++)); do
if [[ "${_str:$((_i-1)):1}" != "${_str:${_i}:1}" ]]; then
_splitstr+="${_str:$((_i-1)):1}${_delim}"
else
_splitstr+="${_str:$((_i-1)):1}"
fi
done
echo "${_splitstr%"${_delim}"*}"
}
######
# main #
######
print "Original: ${str}"
print " Split: $(_splitonchg "${str}" "${delim}")"
</syntaxhighlight>
{{out}}<pre>
Original: gHHH5YY++///\
Split: g, HHH, 5, YY, ++, ///, \</pre>
=={{header|M2000 Interpreter}}==
Stack New open a new stack object as current stack, and keep the old one. After the end of block execution old stack get back as current stack. Data statement push to bottom (we read from top, so using data we get a FIFO type). Letter$ pops a string or raise an error if no string found at the top of stack.
<syntaxhighlight lang="m2000 interpreter">
Module PrintParts(splitthis$) {
Def string m$, p$
Def long c
Stack New {
if len(splitthis$)=0 then exit
For i=1 to len(splitthis$)
p$=mid$(splitthis$,i,1)
if m$<>p$ then {
if c>0 then data string$(m$, c)
m$=p$
c=1
} else c++
Next i
if c>0 then data string$(m$, c)
While stack.size>1 {
Print letter$+", ";
}
If not empty then Print letter$
}
}
PrintParts "gHHH5YY++///\"
</syntaxhighlight>
=={{header|Maple}}==
Added an additional backlash to escape the \ character at the end.
<syntaxhighlight lang="maple">splitChange := proc(str::string)
local start,i,len;
start := 1;
len := StringTools:-Length(str);
for i from 2 to len do
if str[i] <> str[start] then
printf("%s, ", str[start..i-1]);
start := i:
end if;
end do;
printf("%s", str[start..len]);
end proc;
splitChange("gHHH5YY++///\\");</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|Mathematica}}/{{header|Wolfram Language}}==
The backslash (\) must be escaped with another backslash when defining the string.
<syntaxhighlight lang="mathematica">StringJoin@@Riffle[StringCases["gHHH5YY++///\\", p : (x_) .. -> p], ", "]</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|MiniScript}}==
<syntaxhighlight lang="miniscript">s = "gHHH5YY++///\"
output = []
lastLetter = s[0]
for letter in s
if letter != lastLetter then output.push ", "
output.push letter
lastLetter = letter
end for
print output.join("")</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|Modula-2}}==
<syntaxhighlight lang="modula2">MODULE CharacterChange;
FROM Terminal IMPORT Write,WriteString,WriteLn,ReadChar;
PROCEDURE Split(str : ARRAY OF CHAR);
VAR
i : CARDINAL;
c : CHAR;
BEGIN
FOR i:=0 TO HIGH(str) DO
IF i=0 THEN
c := str[i]
ELSIF str[i]#c THEN
c := str[i];
WriteLn;
END;
Write(c)
END
END Split;
CONST EX = "gHHH5YY++///\";
BEGIN
Split(EX);
ReadChar
END CharacterChange.</syntaxhighlight>
{{out}}
<pre>g
HHH
5
YY
++
///
\</pre>
=={{header|Nim}}==
<syntaxhighlight lang="nim">proc splitOnDiff(str: string): string =
result = ""
if str.len < 1: return result
var prevChar: char = str[0]
for idx in 0 ..< str.len:
if str[idx] != prevChar:
result &= ", "
prevChar = str[idx]
result &= str[idx]
assert splitOnDiff("""X""") == """X"""
assert splitOnDiff("""XX""") == """XX"""
assert splitOnDiff("""XY""") == """X, Y"""
assert splitOnDiff("""gHHH5YY++///\""") == """g, HHH, 5, YY, ++, ///, \"""
echo splitOnDiff("""gHHH5YY++///\""")</syntaxhighlight>
{{output}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|ooRexx}}==
<syntaxhighlight lang="oorexx">Parse Arg str . /*obtain optional arguments from the CL*/
If str=='' Then str= 'gHHH5YY++///\' /*Not specified? Then use the default.*/
i=1
ol=''
Do Forever
j=verify(str,substr(str,i,1),'N',i,99) /* find first character that's different */
If j=0 Then Do /* End of strin reached */
ol=ol||substr(str,i) /* the final substring */
Leave
End
ol=ol||substr(str,i,j-i)', ' /* add substring and delimiter */
i=j
End
Say ol</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|Pascal}}==
<syntaxhighlight lang="pascal">program SplitChars;
{$IFDEF FPC}
{$MODE DELPHI}{$COPERATORS ON}
{$ENDIF}
const
TestString = 'gHHH5YY++///\';
function SplitAtChars(const S: String):String;
var
i : integer;
lastChar:Char;
begin
result := '';
IF length(s) > 0 then
begin
LastChar := s[1];
result := LastChar;
For i := 2 to length(s) do
begin
if s[i] <> lastChar then
begin
lastChar := s[i];
result += ', ';
end;
result += LastChar;
end;
end;
end;
BEGIN
writeln(SplitAtChars(TestString));
end.</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|Perl}}==
<syntaxhighlight lang="perl">use strict;
use warnings;
use feature 'say';
use utf8;
binmode(STDOUT, ':utf8');
for my $string (q[gHHH5YY++///\\], q[fffn⃗n⃗n⃗»»» ℵℵ☄☄☃☃̂☃🤔🇺🇸🤦♂️👨👩👧👦]) {
my @S;
my $last = '';
while ($string =~ /(\X)/g) {
if ($last eq $1) { $S[-1] .= $1 } else { push @S, $1 }
$last = $1;
}
say "Orginal: $string\n Split: 「" . join('」, 「', @S) . "」\n";
}</syntaxhighlight>
{{out}}
<pre>Orginal: gHHH5YY++///\
Split: 「g」, 「HHH」, 「5」, 「YY」, 「++」, 「///」, 「\」
Orginal: fffn⃗n⃗n⃗»»» ℵℵ☄☄☃☃̂☃🤔🇺🇸🤦♂️👨👩👧👦
Split: 「fff」, 「」, 「n⃗n⃗n⃗」, 「»»»」, 「 」, 「ℵℵ」, 「☄☄」, 「☃」, 「☃̂」, 「☃」, 「🤔」, 「🇺🇸」, 「🤦♂️」, 「👨👩👧👦」</pre>
=={{header|Phix}}==
<!--<syntaxhighlight lang="phix">-->
<span style="color: #008080;">function</span> <span style="color: #000000;">split_on_change</span><span style="color: #0000FF;">(</span><span style="color: #004080;">string</span> <span style="color: #000000;">s</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">string</span> <span style="color: #000000;">res</span> <span style="color: #0000FF;">=</span> <span style="color: #008000;">""</span>
<span style="color: #008080;">if</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">s</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">then</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">prev</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">s</span><span style="color: #0000FF;">[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">]</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">s</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">ch</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">s</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">ch</span><span style="color: #0000FF;">!=</span><span style="color: #000000;">prev</span> <span style="color: #008080;">then</span>
<span style="color: #000000;">res</span> <span style="color: #0000FF;">&=</span> <span style="color: #008000;">", "</span>
<span style="color: #000000;">prev</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">ch</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #000000;">res</span> <span style="color: #0000FF;">&=</span> <span style="color: #000000;">ch</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">return</span> <span style="color: #000000;">res</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
<span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">split_on_change</span><span style="color: #0000FF;">(</span><span style="color: #008000;">`gHHH5YY++///\`</span><span style="color: #0000FF;">))</span>
<!--</syntaxhighlight>-->
{{Out}}
<pre>
g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|Phixmonti}}==
<syntaxhighlight lang="Phixmonti">/# Rosetta Code problem: https://rosettacode.org/wiki/Split_a_character_string_based_on_change_of_character
by Galileo, 11/2022 #/
include ..\Utilitys.pmt
""
"gHHH5YY++///\" 1 get >ps
len for get
dup tps == if
rot swap chain swap
else
ps> drop >ps
swap ", " tps chain chain swap
endif
endfor
pstack</syntaxhighlight>
{{out}}
<pre>
["g, HHH, 5, YY, ++, ///, \", "gHHH5YY++///\"]
=== Press any key to exit ===</pre>
=={{header|PicoLisp}}==
<syntaxhighlight lang="picolisp">(de splitme (Str)
(let (Str (chop Str) Fin)
(glue
", "
(make
(for X Str
(if (= X (car Fin))
(conc Fin (cons X))
(link (setq Fin (cons X))) ) ) ) ) ) )
(prinl (splitme "gHHH5YY++///\\"))</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|Pike}}==
<syntaxhighlight lang="pike">
string input = "gHHH5YY++///\\"; // \ needs escaping
string last_char;
foreach(input/1, string char) {
if(last_char && char != last_char)
write(", ");
write(char);
last_char = char;
}
</syntaxhighlight>
{{Out}}
<pre>
g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|Plain English}}==
To make sense of this example, you must understand riders. A rider is a simple abstraction for efficiently parsing strings. A rider is a record with an original substring, a source substring, and a token substring.
After executing the following code, for example:
<syntaxhighlight lang="plainenglish">Put "abcdef" into a string.
Slap a rider on the string.</syntaxhighlight>
The rider looks like this:
<syntaxhighlight lang="plainenglish">Original: "abcdef"
Source: "abcdef"
Token: ""</syntaxhighlight>
Now when we <code>Bump the rider.</code>, it looks like this:
<syntaxhighlight lang="plainenglish">Original: "abcdef"
Source: "bcdef"
Token: "a"</syntaxhighlight>
Another bump, and:
<syntaxhighlight lang="plainenglish">Original: "abcdef"
Source: "cdef"
Token: "ab"</syntaxhighlight>
Now let's say we have a complete token and want to start a new one. We can
<code>Position the rider's token on the rider's source.</code>
and now the rider looks like this:
<syntaxhighlight lang="plainenglish">Original: "abcdef"
Source: "cdef"
Token: ""</syntaxhighlight>
And that's all there is to it.
<syntaxhighlight lang="plainenglish">To run:
Start up.
Split "gHHH5YY++///\" into some string things by change of character.
Write the string things on the console.
Destroy the string things.
Wait for the escape key.
Shut down.
To split a string into some string things by change of character:
If the string's length is less than 2, add the string to the string things; exit.
Slap a rider on the string.
Loop.
Move the rider (change of character rules).
Add the rider's token to the string things.
If the rider's source is blank, exit.
Repeat.
To move a rider (change of character rules):
Position the rider's token on the rider's source.
Loop.
If the rider's source is blank, exit.
If the rider's token is blank, bump the rider; repeat.
Put the rider's token's last plus 1 into a byte pointer.
If the rider's token's last's target is not the byte pointer's target, exit.
Bump the rider.
Repeat.
To write some string things to a console;
To write some string things on a console:
Get a string thing from the string things.
Loop.
If the string thing is nil, write "" on the console; exit.
Write the string thing's string on the console without advancing.
If the string thing's next is not nil, write ", " on the console without advancing.
Put the string thing's next into the string thing.
Repeat.</syntaxhighlight>
{{out}}
<pre>
g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|PowerShell}}==
{{trans|BBC BASIC}}
<syntaxhighlight lang="powershell">
function Split-String ([string]$String)
{
[string]$c = $String.Substring(0,1)
[string]$splitString = $c
for ($i = 1; $i -lt $String.Length; $i++)
{
[string]$d = $String.Substring($i,1)
if ($d -ne $c)
{
$splitString += ", "
$c = $d
}
$splitString += $d
}
$splitString
}
</syntaxhighlight>
<syntaxhighlight lang="powershell">
Split-String "gHHH5YY++///\"
</syntaxhighlight>
{{Out}}
<pre>
g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|PureBasic}}==
<syntaxhighlight lang="purebasic">Procedure splitstring(s$)
Define *p.Character = @s$,
c_buf.c = *p\c
While *p\c
If *p\c = c_buf
Print(Chr(c_buf))
Else
Print(", ")
c_buf = *p\c
Continue
EndIf
*p + SizeOf(Character)
Wend
EndProcedure
If OpenConsole()
splitstring("gHHH5YY++///\")
Input()
EndIf</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|Python}}==
===Python3.6+===
Using [[https://docs.python.org/3.6/library/itertools.html#itertools.groupby itertools.groupby]].
<syntaxhighlight lang="python">from itertools import groupby
def splitter(text):
return ', '.join(''.join(group) for key, group in groupby(text))
if __name__ == '__main__':
txt = 'gHHH5YY++///\\' # Note backslash is the Python escape char.
print(f'Input: {txt}\nSplit: {splitter(txt)}')</syntaxhighlight>
{{out}}
<pre>Input: gHHH5YY++///\
Split: g, HHH, 5, YY, ++, ///, \</pre>
===Python: Using zip===
<syntaxhighlight lang="python">def splitterz(text):
return (''.join(x + ('' if x == nxt else ', ')
for x, nxt in zip(txt, txt[1:] + txt[-1])))
if __name__ == '__main__':
txt = 'gHHH5YY++///\\'
print(splitterz(txt))</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
===Python2===
<syntaxhighlight lang="python">import itertools
try: input = raw_input
Line 35 ⟶ 2,356:
groups.append(''.join(g))
print(' input string: %s' % s)
print(' output string: %s' % ', '.join(groups))</
{{out}} when using the default input:
<pre>
Line 41 ⟶ 2,362:
output string: g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|Quackery}}==
<syntaxhighlight lang="quackery">[ dup size 2 <
iff size done
behead swap
[] nested join
witheach
[ over != if
[ drop i^ 1+
conclude ] ] ] is $run ( $ --> n )
[ dup size 2 < if done
dup $run split
dup [] =
iff drop done
dip [ $ ", " join ]
recurse join ] is runs$ ( $ --> $ )
</syntaxhighlight>
'''Testing in Quackery shell.'''
<pre>/O> $ "gHHH5YY++///\" runs$ echo$
...
g, HHH, 5, YY, ++, ///, \
Stack empty.
</pre>
=={{header|Racket}}==
{{trans|Python}}
<syntaxhighlight lang="racket">#lang racket
(define (split-strings-on-change s)
(map list->string (group-by values (string->list s) char=?)))
(displayln (string-join (split-strings-on-change #<<<
gHHH5YY++///\
<
)
", "))</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|Raku}}==
(formerly Perl 6)
{{works with|Rakudo|2017.05}}
<syntaxhighlight lang="raku" line>sub group-chars ($str) { $str.comb: / (.) $0* / }
# Testing:
for Q[gHHH5YY++///\], Q[fffn⃗n⃗n⃗»»» ℵℵ☄☄☃☃̂☃🤔🇺🇸🤦♂️👨👩👧👦] -> $string {
put 'Original: ', $string;
put ' Split: ', group-chars($string).join(', ');
}</syntaxhighlight>
{{out}}
<pre>
Original: gHHH5YY++///\
Split: g, HHH, 5, YY, ++, ///, \
Original: fffn⃗n⃗n⃗»»» ℵℵ☄☄☃☃̂☃🤔🇺🇸🤦♂️👨👩👧👦
Split: fff, , n⃗n⃗n⃗, »»», , ℵℵ, ☄☄, ☃, ☃̂, ☃, 🤔, 🇺🇸, 🤦♂️, 👨👩👧👦
</pre>
The second test-case is to show that Raku works with strings on the Unicode grapheme level, handles whitespace, combiners, and zero width characters up to Unicode Version 13.0 correctly. (Raku generally tracks updates to the Unicode spec and typically lags no more than a month behind.) For those of you with browsers unable to display the second string, it consists of:
* {LATIN SMALL LETTER F} x 3
* {ZERO WIDTH NO-BREAK SPACE} x 3
* {LATIN SMALL LETTER N, COMBINING RIGHT ARROW ABOVE} x 3
* {RIGHT-POINTING DOUBLE ANGLE QUOTATION MARK} x 3
* {SPACE} x 2,
* {ALEF SYMBOL} x 2,
* {COMET} x 2,
* {SNOWMAN} x 1,
* {SNOWMAN, COMBINING CIRCUMFLEX ACCENT} x 1
* {SNOWMAN} x 1,
* {THINKING FACE} x 1
* {REGIONAL INDICATOR SYMBOL LETTER U, REGIONAL INDICATOR SYMBOL LETTER S} x 1
* {FACE PALM, ZERO WIDTH JOINER, MALE SIGN, VARIATION SELECTOR-16} x 1
* {MAN, ZERO WIDTH JOINER, WOMAN, ZERO WIDTH JOINER, GIRL, ZERO WIDTH JOINER, BOY} x 1
=={{header|REXX}}==
===version 1===
<syntaxhighlight lang="rexx">/*REXX program splits a string based on change of character ───► a comma delimited list.*/
parse arg str /*obtain optional arguments from the CL*/
if str=='' then str= 'gHHH5YY++///\' /*Not specified? Then use the default.*/
p=left(str, 1) /*placeholder for the "previous" string*/
$= /* " " " output " */
p=@; $=$ || @
end
say ' input string: ' str /*display the original string & output.*/
say ' output string: ' $ /*stick a fork in it, we're all done. */</syntaxhighlight>
{{out|output|text= when using the default input:}}
<pre>
input string: gHHH5YY++///\
output string: g, HHH, 5, YY, ++, ///, \
</pre>
===version 2===
<syntaxhighlight lang="rexx">/* REXX */
Parse arg str /*obtain optional arguments from the CL*/
if str=='' then str= 'gHHH5YY++///\' /*Not specified? Then use the default.*/
input=str
x=''
cp=''
result=''
Do While str<>''
Parse Var str c +1 str
If c==cp Then x=x||c
Else Do
If x>>'' Then
result=result||x', '
x=c
End
cp=c
End
result=result||x
say ' input string: ' input
say ' output string: ' result </syntaxhighlight>
{{out]]
<pre> input string: gHHH5YY++///\
output string: g, HHH, 5, YY, ++, ///, \</pre>
=={{header|Ring}}==
<syntaxhighlight lang="ring">
see split("gHHH5YY++///\")
func split(s )
c =left (s, 1)
split = ""
for i = 1 to len(s)
d = substr(s, i, 1)
if d != c
split = split + ", "
c = d
ok
split = split + d
next
return split
</syntaxhighlight>
Output:
<pre>
g, HHH, 5, YY,
</pre>
=={{header|RPL}}==
≪ → text
≪ "" text 1 1 SUB
1 text SIZE '''FOR''' j
text j DUP SUB
'''IF''' DUP2 ≠ '''THEN''' SWAP DROP ", " OVER + '''END'''
ROT SWAP + SWAP
'''NEXT '''DROP
≫ ≫ ‘<span style="color:blue">COMASPLT</span>’ STO
=={{header|Ruby}}==
<syntaxhighlight lang="ruby">def split(str)
puts " input string: #{str}"
s = str.chars.chunk(&:itself).map{|_,a| a.join}.join(", ")
puts "output string: #{s}"
s
end
split("gHHH5YY++///\\")</syntaxhighlight>
{{out}}
<pre>
input string: gHHH5YY++///\
output string: g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|Rust}}==
<syntaxhighlight lang="rust">fn splitter(string: &str) -> String {
let chars: Vec<_> = string.chars().collect();
let mut result = Vec::new();
let mut last_mismatch = 0;
for i in 0..chars.len() {
if chars.len() == 1 {
return chars[0..1].iter().collect();
}
if i > 0 && chars[i-1] != chars[i] {
let temp_result: String = chars[last_mismatch..i].iter().collect();
result.push(temp_result);
last_mismatch = i;
}
if i == chars.len() - 1 {
let temp_result: String = chars[last_mismatch..chars.len()].iter().collect();
result.push(temp_result);
}
}
result.join(", ")
}
fn main() {
let test_string = "g";
println!("input string: {}", test_string);
println!("output string: {}", splitter(test_string));
let test_string = "";
println!("input string: {}", test_string);
println!("output string: {}", splitter(test_string));
let test_string = "gHHH5YY++///\\";
println!("input string: {}", test_string);
println!("output string: {}", splitter(test_string));
}</syntaxhighlight>
{{out}}
<pre>
input string: g
output string: g
input string:
output string:
input string: gHHH5YY++///\
output string: g, HHH, 5, YY, ++, ///, \
</pre>
===Alternate using IterTools===
<syntaxhighlight lang="rust">use itertools::Itertools;
pub fn split_text(s: &str) -> Vec<String> {
let mut r = Vec::new();
for (_, group) in &s.chars().into_iter().group_by(|e| *e) {
r.push(group.map(|e| e.to_string()).join(""));
}
r
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_splitting_text() {
assert_eq!(split_text("gHHH5YY++///\\"), vec!["g", "HHH", "5", "YY", "++", "///", "\\"]);
assert!(split_text("").is_empty());
}
}
</syntaxhighlight>
=={{header|Scala}}==
<syntaxhighlight lang="scala">// Split a (character) string into comma (plus a blank) delimited strings
// based on a change of character (left to right).
// See https://rosettacode.org/wiki/Split_a_character_string_based_on_change_of_character#Scala
def runLengthSplit(s: String): String = /// Add a guard letter
(s + 'X').sliding(2).map(pair => pair.head + (if (pair.head != pair.last) ", " else "")).mkString("")
println(runLengthSplit("""gHHH5YY++///\"""))</syntaxhighlight>
{{Out}}See it in running in your browser by [https://scalafiddle.io/sf/c4dp8GT/2 ScalaFiddle (JavaScript)]
or by [https://scastie.scala-lang.org/mDoBS77YSG2Z7w5xdAPzcw Scastie (JVM)].
<syntaxhighlight lang="scala">
def runLengthSplit(s:String):List[String] = {
def recursiveSplit(acc:List[String], rest:String): List[String] = rest match {
case "" => acc
case _ => {
val (h, t) = rest.span(_ == rest.head)
recursiveSplit(acc :+ h, t)
}
}
recursiveSplit(Nil, s)
}
val result = runLengthSplit("""gHHH5YY++///\""")
println(result.mkString(","))
</syntaxhighlight>
{{Out}}
<pre>
g,HHH,5,YY,++,///,\
</pre>
=={{header|Sed}}==
<syntaxhighlight lang="sed">echo 'gHHH5YY++///\' | sed 's/\(.\)\1*/&, /g;s/, $//'</syntaxhighlight>
Output:
g, HHH, 5, YY, ++, ///, \
=={{header|Sidef}}==
<syntaxhighlight lang="ruby">func group(str) {
gather {
while (var match = (str =~ /((.)\g{-1}*)/g)) {
take(match[0])
}
}
}
say group(ARGV[0] \\ 'gHHH5YY++///\\').join(', ')</syntaxhighlight>
{{out}}
<pre>
g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|SNOBOL4}}==
{{works with|SNOBOL4, SPITBOL for Linux}}
<syntaxhighlight lang="snobol4">
* Program: split_on_change_of_character.sbl
* To run: sbl split_on_change_of_character.sbl
* Description: Split a (character) string into comma (plus a blank)
* delimited strings based on a change of character (left to right).
*
* Blanks should be treated as any other character
* (except they are problematic to display clearly).
* The same applies to commas.
*
* For instance, the string:
*
* gHHH5YY++///\
* should be split and show:
*
* g, HHH, 5, YY, ++, ///, \
* Comment: Tested using the Spitbol for Linux version of SNOBOL4
lf = substr(&alphabet,11,1) ;* New line or line feed
* Function split_cc will split a string on a change of character.
define('split_cc(s)tchar,target,post')
:(split_cc_end)
split_cc
tchar = substr(s,1,1) :f(freturn)
split_cc_pat = span(*tchar) . target (rpos(0) | len(1) . tchar rem) . post
split_cc2
s ? split_cc_pat = post :f(split_cc3)
split_cc = (ident(split_cc) target, split_cc ', ' target) :s(split_cc2)
split_cc3
:(return)
split_cc_end
test_string = "gHHH5YY++///\"
output = test_string lf
split_string = split_cc(test_string)
output = split_string
END</syntaxhighlight>
{{out}}
<pre>
gHHH5YY++///\
g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|Standard ML}}==
<syntaxhighlight lang="sml">(*
* Head-Tail implementation of grouping
*)
fun group' ac nil = [ac]
| group' nil (y::ys) = group' [y] ys
| group' (x::ac) (y::ys) = if x=y then group' (y::x::ac) ys else (x::ac) :: group' [y] ys
fun group xs = group' nil xs
fun groupString str = String.concatWith ", " (map implode (group (explode str)))</syntaxhighlight>
{{out}}
<pre>- groupString "gHHH5YY++///\\";
val it = "g, HHH, 5, YY, ++, ///, \\" : string</pre>
=={{header|Swift}}==
<syntaxhighlight lang="swift">public extension String {
func splitOnChanges() -> [String] {
guard !isEmpty else {
return []
}
var res = [String]()
var workingChar = first!
var workingStr = "\(workingChar)"
for char in dropFirst() {
if char != workingChar {
res.append(workingStr)
workingStr = "\(char)"
workingChar = char
} else {
workingStr += String(char)
}
}
res.append(workingStr)
return res
}
}
print("gHHH5YY++///\\".splitOnChanges().joined(separator: ", "))</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|Tailspin}}==
<syntaxhighlight lang="tailspin">
composer splitEquals
<reps> <nextReps>*
rule reps: <'(.)\1*'>
rule nextReps: <reps> -> \(', ' ! $ ! \)
end splitEquals
'gHHH5YY++///\' -> splitEquals -> !OUT::write
</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|tbas}}==
{{Trans|BBC BASIC}}
<syntaxhighlight lang="basic">SUB SPLITUNIQUE$(s$)
DIM c$, d$, split$, i%
c$ = LEFT$(s$, 1)
split$ = ""
FOR i% = 1 TO LEN(s$)
d$ = MID$(s$, i%, 1)
IF d$ <> c$ THEN
split$ = split$ + ", "
c$ = d$
END IF
split$ = split$ + d$
NEXT
RETURN split$
END SUB
PRINT SPLITUNIQUE$("gHHH5YY++///\")
END</syntaxhighlight>
=={{header|Tcl}}==
This is most concise with regular expressions. Note well the two steps: it could be achieved in one very clever regexp, but being that clever is usually a bad idea (for both readability and performance, in this case).
<syntaxhighlight lang="tcl">set string "gHHH5YY++///\\"
regsub -all {(.)\1*} $string {\0, } string
regsub {, $} $string {} string
puts $string</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|Transd}}==
The task doesn't state explicitly about the order in which substrings should be
displayed. So, here are two variants: one is order-preserving, the other is not
order-preserving.
<syntaxhighlight lang="Scheme">#lang transd
MainModule: {
s: "gHHH5YY++///\\",
_start: (λ
(with res ""
(for c in (split s "") do
(if (neq Char(c) (back res)) (+= res ", "))
(+= res c))
(textout res))
(lout "Second variant: ")
(for v in (values (group-by (split s ""))) do
(textout (if @idx ", ") (join v "")))
)
}</syntaxhighlight>
{{out}}
<pre>
g, HHH, 5, YY, ++, ///, \
Second variant:
++, ///, 5, HHH, YY, \, g
</pre>
=={{header|VBA}}==
<syntaxhighlight lang="vb">
Option Explicit
Sub Split_string_based_on_change_character()
Dim myArr() As String, T As String
Const STRINPUT As String = "gHHH5YY++///\"
Const SEP As String = ", "
myArr = Split_Special(STRINPUT)
T = Join(myArr, SEP)
Debug.Print Left(T, Len(T) - Len(SEP))
End Sub
Function Split_Special(Ch As String) As String()
'return an array of Strings
Dim tb, i&, st As String, cpt As Long, R() As String
tb = Split(StrConv(Ch, vbUnicode), Chr(0))
st = tb(LBound(tb))
ReDim R(cpt)
R(cpt) = st
For i = 1 To UBound(tb)
If tb(i) = st Then
R(cpt) = R(cpt) & st
Else
st = tb(i)
cpt = cpt + 1
ReDim Preserve R(cpt)
R(cpt) = st
End If
Next
Split_Special = R
End Function
</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|V (Vlang)}}==
<syntaxhighlight lang="v (vlang)">fn main() {
println(splitter('gHHH5YY++///\\')) \\ The "\" character needs to be escaped.
}
fn splitter(text string) string {
mut check := text.substr(0, 1)
mut new_text, mut temp := '', ''
for index, _ in text {
temp = text.substr(index, index + 1)
if temp != check {
new_text = new_text + ', '
check = temp
}
new_text = new_text + temp
}
return new_text
}
</syntaxhighlight>
{{out}}
<pre>
g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|Wren}}==
<syntaxhighlight lang="wren">var split = Fn.new { |s|
if (s.count == 0) return ""
var res = []
var last = s[0]
var curr = last
for (c in s.skip(1)) {
if (c == last) {
curr = curr + c
} else {
res.add(curr)
curr = c
}
last = c
}
res.add(curr)
return res.join(", ")
}
var s = "gHHH5YY++///\\"
System.print(split.call(s))</syntaxhighlight>
{{out}}
<pre>
g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|XLISP}}==
<syntaxhighlight lang="lisp">(defun delimit (s)
(defun delim (old-list new-list current-char)
(if (null old-list)
new-list
(delim (cdr old-list) (append new-list
(if (not (equal (car old-list) current-char))
`(#\, #\Space ,(car old-list))
(cons (car old-list) nil) ) )
(car old-list) ) ) )
(list->string (delim (string->list s) '() (car (string->list s)))) )
(display (delimit "gHHH5YY++///\\")) ;; NB. The "\" character needs to be escaped</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
=={{header|XPL0}}==
<syntaxhighlight lang="xpl0">string 0; \change to zero-terminated convention
char S;
[S:= "gHHH5YY++///\";
while S(0) do
[ChOut(0, S(0));
if S(1)#S(0) & S(1)#0 then Text(0, ", ");
S:= S+1;
];
]</syntaxhighlight>
{{out}}
<pre>
g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|Yabasic}}==
<syntaxhighlight lang="freebasic">sub esplit$(instring$)
if len(instring$) < 2 return instring$
ret$ = left$(instring$,1)
for i = 2 to len(instring$)
if mid$(instring$,i,1) <> mid$(instring$, i - 1, 1) ret$ = ret$ + ", "
ret$ = ret$ + mid$(instring$, i, 1)
next i
return ret$
end sub
print esplit$("gHHH5YY++///\\")</syntaxhighlight>
=={{header|Z80 Assembly}}==
<syntaxhighlight lang="z80">PrintChar equ &BB5A ;Amstrad CPC BIOS call
Terminator equ 0 ;marks the end of a string
org &8000
LD HL,StringA
loop:
ld a,(HL) ;load a char from (HL)
cp Terminator ;is it the terminator?
ret z ;if so, exit
ld e,a ;store this char in E temporarily
inc hl ;next char
ld a,(HL) ;get next char
cp Terminator ;is the next char the terminator?
jp z,StringDone ;if so, print E and exit.
;needed to prevent the last char from getting a comma and space.
dec hl ;go back one so we don't skip any chars
cp e ;does (HL) == (HL+1)?
push af
ld a,e
call PrintChar ;either way, print E to screen.
pop af ;retrieve the results of the last compare.
jr z,SkipComma ;if A=E, no comma or space. Just loop again.
ld a,','
call PrintChar
ld a,' '
call PrintChar
SkipComma:
inc hl ;next char
jp loop ;back to start
StringDone:
ld a,e ;last character in string is printed here.
jp PrintChar
ReturnToBasic:
RET
StringA:
byte "gHHH5YY++///\",0</syntaxhighlight>
{{out}}
<pre>
g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|zkl}}==
<syntaxhighlight lang="zkl">fcn group(str){
C,out := str[0],Sink(C);
foreach c in (str[1,*]){ out.write(if(c==C) c else String(", ",C=c)) }
out.close();
}
group("gHHH5YY++///\\").println();</syntaxhighlight>
{{out}}
<pre>
g, HHH, 5, YY, ++, ///, \
</pre>
=={{header|ZX Spectrum Basic}}==
<syntaxhighlight lang="basic"> 10 LET s$="gHHH5YY++///\"
20 LET c$=s$(1)
30 LET n$=c$
40 FOR i=2 TO LEN s$
50 IF s$(i)<>c$ THEN LET n$=n$+", "
60 LET n$=n$+s$(i)
70 LET c$=s$(i)
80 NEXT i
90 PRINT n$</syntaxhighlight>
{{out}}
<pre>g, HHH, 5, YY, ++, ///, \</pre>
| |||