Determine if a string is squeezable

From Rosetta Code
Task
Determine if a string is squeezable
You are encouraged to solve this task according to the task description, using any language you may know.

Determine if a character string is   squeezable.

And if so,   squeeze the string   (by removing any number of a   specified   immediately repeated   character).


This task is very similar to the task     Determine if a character string is collapsible     except that only a specified character is   squeezed   instead of any character that is immediately repeated.


If a character string has a specified   immediately repeated   character(s),   the repeated characters are to be deleted (removed),   but not the primary (1st) character(s).


A specified   immediately repeated   character is any specified character that is   immediately   followed by an identical character (or characters).   Another word choice could've been   duplicated character,   but that might have ruled out   (to some readers)   triplicated characters   ···   or more.


{This Rosetta Code task was inspired by a newly introduced   (as of around November 2019)   PL/I   BIF:   squeeze.}


Examples

In the following character string with a specified   immediately repeated   character of   e:


 The better the 4-wheel drive, the further you'll be from help when ya get stuck! 


Only the 2nd   e   is an specified repeated character,   indicated by an underscore (above),   even though they (the characters) appear elsewhere in the character string.


So, after squeezing the string, the result would be:

 The better the 4-whel drive, the further you'll be from help when ya get stuck! 



Another example: In the following character string,   using a specified immediately repeated character   s:

 headmistressship 


The "squeezed" string would be:

 headmistreship 


Task

Write a subroutine/function/procedure/routine···   to locate a   specified immediately repeated   character and   squeeze   (delete)   them from the character string.   The character string can be processed from either direction.


Show all output here, on this page:

  •   the   specified repeated character   (to be searched for and possibly squeezed):
  •   the   original string and its length
  •   the resultant string and its length
  •   the above strings should be "bracketed" with   <<<   and   >>>   (to delineate blanks)
  •   «««Guillemets may be used instead for "bracketing" for the more artistic programmers,   shown used here»»»


Use (at least) the following five strings,   all strings are length seventy-two (characters, including blanks),   except the 1st string:

                                                                                  immediately
 string                                                                            repeated
 number                                                                            character
                                                                                     ( ↓   a blank,  a minus,  a seven,  a period)
        ╔╗
   1    ║╚═══════════════════════════════════════════════════════════════════════╗    ' '    ◄■■■■■■  a null string  (length zero)
   2    ║"If I were two-faced, would I be wearing this one?" --- Abraham Lincoln ║    '-'
   3    ║..1111111111111111111111111111111111111111111111111111111111111117777888║    '7'
   4    ║I never give 'em hell, I just tell the truth, and they think it's hell. ║    '.'
   5    ║                                                    --- Harry S Truman  ║  (below)  ◄■■■■■■  has many repeated blanks
        ╚════════════════════════════════════════════════════════════════════════╝     ↑
                                                                                       │
                                                                                       │
        For the 5th string  (Truman's signature line),  use each of these  specified immediately  repeated characters:
                                  •  a blank
                                  •  a minus
                                  •  a lowercase  r


Note:   there should be seven results shown,   one each for the 1st four strings,   and three results for the 5th string.


Related tasks




AWK[edit]

 
# syntax: GAWK -f DETERMINE_IF_A_STRING_IS_SQUEEZABLE.AWK
BEGIN {
arr[++n] = ""  ; arr2[n] = " "
arr[++n] = "\"If I were two-faced, would I be wearing this one?\" --- Abraham Lincoln "  ; arr2[n] = "-"
arr[++n] = "..1111111111111111111111111111111111111111111111111111111111111117777888"  ; arr2[n] = "7"
arr[++n] = "I never give 'em hell, I just tell the truth, and they think it's hell. "  ; arr2[n] = "."
arr[++n] = " --- Harry S Truman "  ; arr2[n] = " -r"
arr[++n] = "The better the 4-wheel drive, the further you'll be from help when ya get stuck!" ; arr2[n] = "e"
arr[++n] = "headmistressship"  ; arr2[n] = "s"
for (i=1; i<=n; i++) {
for (j=1; j<=length(arr2[i]); j++) {
main(arr[i],substr(arr2[i],j,1))
}
}
exit(0)
}
function main(str,chr, c,i,new_str,prev_c) {
for (i=1; i<=length(str); i++) {
c = substr(str,i,1)
if (!(prev_c == c && c == chr)) {
prev_c = c
new_str = new_str c
}
}
printf("use: '%s'\n",chr)
printf("old: %2d <<<%s>>>\n",length(str),str)
printf("new: %2d <<<%s>>>\n\n",length(new_str),new_str)
}
 
Output:
use: ' '
old:  0 <<<>>>
new:  0 <<<>>>

use: '-'
old: 72 <<<"If I were two-faced, would I be wearing this one?" --- Abraham Lincoln >>>
new: 70 <<<"If I were two-faced, would I be wearing this one?" - Abraham Lincoln >>>

use: '7'
old: 72 <<<..1111111111111111111111111111111111111111111111111111111111111117777888>>>
new: 69 <<<..1111111111111111111111111111111111111111111111111111111111111117888>>>

use: '.'
old: 72 <<<I never give 'em hell, I just tell the truth, and they think it's hell. >>>
new: 72 <<<I never give 'em hell, I just tell the truth, and they think it's hell. >>>

use: ' '
old: 72 <<<                                                    --- Harry S Truman  >>>
new: 20 <<< --- Harry S Truman >>>

use: '-'
old: 72 <<<                                                    --- Harry S Truman  >>>
new: 70 <<<                                                    - Harry S Truman  >>>

use: 'r'
old: 72 <<<                                                    --- Harry S Truman  >>>
new: 71 <<<                                                    --- Hary S Truman  >>>

use: 'e'
old: 80 <<<The better the 4-wheel drive, the further you'll be from help when ya get stuck!>>>
new: 79 <<<The better the 4-whel drive, the further you'll be from help when ya get stuck!>>>

use: 's'
old: 16 <<<headmistressship>>>
new: 14 <<<headmistreship>>>

C[edit]

Identical implementation as in Determine_if_a_string_is_collapsible, as both tasks are very similar. The Lincoln quote contains backslashes to accommodate the double quotes via the command line. strcmpi is not part of the C Standard Library, thus comment out the definition in the code if testing on a system where it is already included.

 
#include<string.h>
#include<stdlib.h>
#include<stdio.h>
 
#define COLLAPSE 0
#define SQUEEZE 1
 
typedef struct charList{
char c;
struct charList *next;
} charList;
 
/*
Implementing strcmpi, the case insensitive string comparator, as it is not part of the C Standard Library.
 
Comment this out if testing on a compiler where it is already defined.
*/

 
int strcmpi(char str1[100],char str2[100]){
int len1 = strlen(str1), len2 = strlen(str2), i;
 
if(len1!=len2){
return 1;
}
 
else{
for(i=0;i<len1;i++){
if((str1[i]>='A'&&str1[i]<='Z')&&(str2[i]>='a'&&str2[i]<='z')&&(str2[i]-65!=str1[i]))
return 1;
else if((str2[i]>='A'&&str2[i]<='Z')&&(str1[i]>='a'&&str1[i]<='z')&&(str1[i]-65!=str2[i]))
return 1;
else if(str1[i]!=str2[i])
return 1;
}
}
 
return 0;
}
 
charList *strToCharList(char* str){
int len = strlen(str),i;
 
charList *list, *iterator, *nextChar;
 
list = (charList*)malloc(sizeof(charList));
list->c = str[0];
list->next = NULL;
 
iterator = list;
 
for(i=1;i<len;i++){
nextChar = (charList*)malloc(sizeof(charList));
nextChar->c = str[i];
nextChar->next = NULL;
 
iterator->next = nextChar;
iterator = nextChar;
}
 
return list;
}
 
char* charListToString(charList* list){
charList* iterator = list;
int count = 0,i;
char* str;
 
while(iterator!=NULL){
count++;
iterator = iterator->next;
}
 
str = (char*)malloc((count+1)*sizeof(char));
iterator = list;
 
for(i=0;i<count;i++){
str[i] = iterator->c;
iterator = iterator->next;
}
 
free(list);
str[i] = '\0';
 
return str;
}
 
char* processString(char str[100],int operation, char squeezeChar){
charList *strList = strToCharList(str),*iterator = strList, *scout;
 
if(operation==SQUEEZE){
while(iterator!=NULL){
if(iterator->c==squeezeChar){
scout = iterator->next;
 
while(scout!=NULL && scout->c==squeezeChar){
iterator->next = scout->next;
scout->next = NULL;
free(scout);
scout = iterator->next;
}
}
iterator = iterator->next;
}
}
 
else{
while(iterator!=NULL && iterator->next!=NULL){
if(iterator->c == (iterator->next)->c){
scout = iterator->next;
squeezeChar = iterator->c;
 
while(scout!=NULL && scout->c==squeezeChar){
iterator->next = scout->next;
scout->next = NULL;
free(scout);
scout = iterator->next;
}
}
iterator = iterator->next;
}
}
 
return charListToString(strList);
}
 
void printResults(char originalString[100], char finalString[100], int operation, char squeezeChar){
if(operation==SQUEEZE){
printf("Specified Operation : SQUEEZE\nTarget Character : %c",squeezeChar);
}
 
else
printf("Specified Operation : COLLAPSE");
 
printf("\nOriginal %c%c%c%s%c%c%c\nLength : %d",174,174,174,originalString,175,175,175,(int)strlen(originalString));
printf("\nFinal  %c%c%c%s%c%c%c\nLength : %d\n",174,174,174,finalString,175,175,175,(int)strlen(finalString));
}
 
int main(int argc, char** argv){
int operation;
char squeezeChar;
 
if(argc<3||argc>4){
printf("Usage : %s <SQUEEZE|COLLAPSE> <String to be processed> <Character to be squeezed, if operation is SQUEEZE>\n",argv[0]);
return 0;
}
 
if(strcmpi(argv[1],"SQUEEZE")==0 && argc!=4){
scanf("Please enter characted to be squeezed : %c",&squeezeChar);
operation = SQUEEZE;
}
 
else if(argc==4){
operation = SQUEEZE;
squeezeChar = argv[3][0];
}
 
else if(strcmpi(argv[1],"COLLAPSE")==0){
operation = COLLAPSE;
}
 
if(strlen(argv[2])<2){
printResults(argv[2],argv[2],operation,squeezeChar);
}
 
else{
printResults(argv[2],processString(argv[2],operation,squeezeChar),operation,squeezeChar);
}
 
return 0;
}
 

Output :

C:\My Projects\networks>a squeeze "The better the 4-wheel drive, the further you'll be from help when ya get stuck!" t
Specified Operation : SQUEEZE
Target Character : t
Original «««The better the 4-wheel drive, the further you'll be from help when ya get stuck!»»»
Length : 80
Final    «««The beter the 4-wheel drive, the further you'll be from help when ya get stuck!»»»
Length : 79

C:\My Projects\networks>a squeeze "The better the 4-wheel drive, the further you'll be from help when ya get stuck!" e
Specified Operation : SQUEEZE
Target Character : e
Original «««The better the 4-wheel drive, the further you'll be from help when ya get stuck!»»»
Length : 80
Final    «««The better the 4-whel drive, the further you'll be from help when ya get stuck!»»»
Length : 79

C:\My Projects\networks>a squeeze "The better the 4-wheel drive, the further you'll be from help when ya get stuck!" l
Specified Operation : SQUEEZE
Target Character : l
Original «««The better the 4-wheel drive, the further you'll be from help when ya get stuck!»»»
Length : 80
Final    «««The better the 4-wheel drive, the further you'l be from help when ya get stuck!»»»
Length : 79

C:\My Projects\networks>a squeeze headmistressship s
Specified Operation : SQUEEZE
Target Character : s
Original «««headmistressship»»»
Length : 16
Final    «««headmistreship»»»
Length : 14

C:\My Projects\networks>a squeeze "" ""
Specified Operation : SQUEEZE
Target Character :
Original «««»»»
Length : 0
Final    «««»»»
Length : 0

C:\My Projects\networks>a squeeze "\"If I were two-faced, would I be wearing this one?\" --- Abraham Lincoln" -
Specified Operation : SQUEEZE
Target Character : -
Original «««"If I were two-faced, would I be wearing this one?" --- Abraham Lincoln»»»
Length : 71
Final    «««"If I were two-faced, would I be wearing this one?" - Abraham Lincoln»»»
Length : 69

C:\My Projects\networks>a squeeze ..1111111111111111111111111111111111111111111111111111111111111117777888 7
Specified Operation : SQUEEZE
Target Character : 7
Original «««..1111111111111111111111111111111111111111111111111111111111111117777888»»»
Length : 72
Final    «««..1111111111111111111111111111111111111111111111111111111111111117888»»»
Length : 69

C:\My Projects\networks>a squeeze "I never give 'em hell, I just tell the truth, and they think it's hell." .
Specified Operation : SQUEEZE
Target Character : .
Original «««I never give 'em hell, I just tell the truth, and they think it's hell.»»»
Length : 71
Final    «««I never give 'em hell, I just tell the truth, and they think it's hell.»»»
Length : 71

C:\My Projects\networks>a squeeze "                                                   ---  Harry S Truman  " " "
Specified Operation : SQUEEZE
Target Character :
Original «««                                                   ---  Harry S Truman  »»»
Length : 72
Final    ««« --- Harry S Truman »»»
Length : 20

C:\My Projects\networks>a squeeze "                                                   ---  Harry S Truman  " -
Specified Operation : SQUEEZE
Target Character : -
Original «««                                                   ---  Harry S Truman  »»»
Length : 72
Final    «««                                                   -  Harry S Truman  »»»
Length : 70

C:\My Projects\networks>a squeeze "                                                   ---  Harry S Truman  " r
Specified Operation : SQUEEZE
Target Character : r
Original «««                                                   ---  Harry S Truman  »»»
Length : 72
Final    «««                                                   ---  Hary S Truman  »»»
Length : 71

Factor[edit]

USING: formatting fry io kernel math sbufs sequences strings ;
IN: rosetta-code.squeeze
 
: (squeeze) ( str c -- new-str )
[ unclip-slice 1string >sbuf ] dip
'[ over last over [ _ = ] both? [ drop ] [ suffix! ] if ]
reduce >string ;
 
: squeeze ( str c -- new-str )
over empty? [ 2drop "" ] [ (squeeze) ] if ;
 
: .str ( str -- ) dup length "«««%s»»» (length %d)\n" printf ;
 
: show-squeeze ( str c -- )
dup "Specified character: '%c'\n" printf
[ "Before squeeze: " write drop .str ]
[ "After squeeze: " write squeeze .str ] 2bi nl ;
 
: squeeze-demo ( -- )
{
""
"\"If I were two-faced, would I be wearing this one?\" --- Abraham Lincoln "
"..1111111111111111111111111111111111111111111111111111111111111117777888"
"I never give 'em hell, I just tell the truth, and they think it's hell. "
} "\0-7." [ show-squeeze ] 2each
 
" --- Harry S Truman "
[ CHAR: space ] [ CHAR: - ] [ CHAR: r ] tri
[ show-squeeze ] [email protected] ;
 
MAIN: squeeze-demo
Output:
Specified character: ' '
Before squeeze: «««»»» (length 0)
After  squeeze: «««»»» (length 0)

Specified character: '-'
Before squeeze: «««"If I were two-faced, would I be wearing this one?" --- Abraham Lincoln »»» (length 72)
After  squeeze: «««"If I were two-faced, would I be wearing this one?" - Abraham Lincoln »»» (length 70)

Specified character: '7'
Before squeeze: «««..1111111111111111111111111111111111111111111111111111111111111117777888»»» (length 72)
After  squeeze: «««..1111111111111111111111111111111111111111111111111111111111111117888»»» (length 69)

Specified character: '.'
Before squeeze: «««I never give 'em hell, I just tell the truth, and they think it's hell. »»» (length 72)
After  squeeze: «««I never give 'em hell, I just tell the truth, and they think it's hell. »»» (length 72)

Specified character: ' '
Before squeeze: «««                                                   ---  Harry S Truman  »»» (length 72)
After  squeeze: ««« --- Harry S Truman »»» (length 20)

Specified character: '-'
Before squeeze: «««                                                   ---  Harry S Truman  »»» (length 72)
After  squeeze: «««                                                   -  Harry S Truman  »»» (length 70)

Specified character: 'r'
Before squeeze: «««                                                   ---  Harry S Truman  »»» (length 72)
After  squeeze: «««                                                   ---  Hary S Truman  »»» (length 71)

Go[edit]

package main
 
import "fmt"
 
// Returns squeezed string, original and new lengths in
// unicode code points (not normalized).
func squeeze(s string, c rune) (string, int, int) {
r := []rune(s)
le, del := len(r), 0
for i := le - 2; i >= 0; i-- {
if r[i] == c && r[i] == r[i+1] {
copy(r[i:], r[i+1:])
del++
}
}
if del == 0 {
return s, le, le
}
r = r[:le-del]
return string(r), le, len(r)
}
 
func main() {
strings := []string{
"",
`"If I were two-faced, would I be wearing this one?" --- Abraham Lincoln `,
"..1111111111111111111111111111111111111111111111111111111111111117777888",
"I never give 'em hell, I just tell the truth, and they think it's hell. ",
" --- Harry S Truman ",
"The better the 4-wheel drive, the further you'll be from help when ya get stuck!",
"headmistressship",
"aardvark",
"😍😀🙌💃😍😍😍🙌",
}
chars := [][]rune{{' '}, {'-'}, {'7'}, {'.'}, {' ', '-', 'r'}, {'e'}, {'s'}, {'a'}, {'😍'}}
 
for i, s := range strings {
for _, c := range chars[i] {
ss, olen, slen := squeeze(s, c)
fmt.Printf("specified character = %q\n", c)
fmt.Printf("original : length = %2d, string = «««%s»»»\n", olen, s)
fmt.Printf("squeezed : length = %2d, string = «««%s»»»\n\n", slen, ss)
}
}
}
Output:
specified character = ' '
original : length =  0, string = «««»»»
squeezed : length =  0, string = «««»»»

specified character = '-'
original : length = 72, string = «««"If I were two-faced, would I be wearing this one?" --- Abraham Lincoln »»»
squeezed : length = 70, string = «««"If I were two-faced, would I be wearing this one?" - Abraham Lincoln »»»

specified character = '7'
original : length = 72, string = «««..1111111111111111111111111111111111111111111111111111111111111117777888»»»
squeezed : length = 69, string = «««..1111111111111111111111111111111111111111111111111111111111111117888»»»

specified character = '.'
original : length = 72, string = «««I never give 'em hell, I just tell the truth, and they think it's hell. »»»
squeezed : length = 72, string = «««I never give 'em hell, I just tell the truth, and they think it's hell. »»»

specified character = ' '
original : length = 72, string = «««                                                   ---  Harry S Truman  »»»
squeezed : length = 20, string = ««« --- Harry S Truman »»»

specified character = '-'
original : length = 72, string = «««                                                   ---  Harry S Truman  »»»
squeezed : length = 70, string = «««                                                   -  Harry S Truman  »»»

specified character = 'r'
original : length = 72, string = «««                                                   ---  Harry S Truman  »»»
squeezed : length = 71, string = «««                                                   ---  Hary S Truman  »»»

specified character = 'e'
original : length = 80, string = «««The better the 4-wheel drive, the further you'll be from help when ya get stuck!»»»
squeezed : length = 79, string = «««The better the 4-whel drive, the further you'll be from help when ya get stuck!»»»

specified character = 's'
original : length = 16, string = «««headmistressship»»»
squeezed : length = 14, string = «««headmistreship»»»

specified character = 'a'
original : length =  8, string = «««aardvark»»»
squeezed : length =  7, string = «««ardvark»»»

specified character = '😍'
original : length =  8, string = «««😍😀🙌💃😍😍😍🙌»»»
squeezed : length =  6, string = «««😍😀🙌💃😍🙌»»»

Julia[edit]

const teststringpairs = [
("", ' '),
(""""If I were two-faced, would I be wearing this one?" --- Abraham Lincoln """, '-'),
("..1111111111111111111111111111111111111111111111111111111111111117777888", '7'),
("""I never give 'em hell, I just tell the truth, and they think it's hell. """, '.'),
(" --- Harry S Truman ", ' '),
(" --- Harry S Truman ", '-'),
(" --- Harry S Truman ", 'r')]
 
function squeezed(s, c)
t = isempty(s) ? "" : s[1:1]
for x in s[2:end]
if x != t[end] || x != c
t *= x
end
end
t
end
 
for (s, c) in teststringpairs
n, t = length(s), squeezed(s, c)
println("«««$s»»» (length $n)\n",
s == t ? "is not squeezed, so remains" : "squeezes to",
":\n«««$t»»» (length $(length(t))).\n")
end
 
Output:
«««»»» (length 0)
is not squeezed, so remains:
«««»»» (length 0).

«««"If I were two-faced, would I be wearing this one?" --- Abraham Lincoln »»» (length 72)
squeezes to:
«««"If I were two-faced, would I be wearing this one?" - Abraham Lincoln »»» (length 70).

«««..1111111111111111111111111111111111111111111111111111111111111117777888»»» (length 72)
squeezes to:
«««..1111111111111111111111111111111111111111111111111111111111111117888»»» (length 69).

«««I never give 'em hell, I just tell the truth, and they think it's hell. »»» (length 72)
is not squeezed, so remains:
«««I never give 'em hell, I just tell the truth, and they think it's hell. »»» (length 72).

«««                                                    --- Harry S Truman  »»» (length 72)
squeezes to:
««« --- Harry S Truman »»» (length 20).

«««                                                    --- Harry S Truman  »»» (length 72)
squeezes to:
«««                                                    - Harry S Truman  »»» (length 70).

«««                                                    --- Harry S Truman  »»» (length 72)
squeezes to:
«««                                                    --- Hary S Truman  »»» (length 71).

Perl[edit]

use strict;
use warnings;
use Unicode::UCD 'charinfo';
 
for (
['', ' '],
['"If I were two-faced, would I be wearing this one?" --- Abraham Lincoln ', '-'],
['..1111111111111111111111111111111111111111111111111111111111111117777888', '7'],
["I never give 'em hell, I just tell the truth, and they think it's hell. ", '.'],
[' --- Harry S Truman ', ' '],
[' --- Harry S Truman ', '-'],
[' --- Harry S Truman ', 'r']
) {
my($phrase,$char) = @$_;
(my $squeeze = $phrase) =~ s/([$char])\1+/$1/g;
printf "\nOriginal length: %d <<<%s>>>\nSqueezable on \"%s\": %s\nSqueezed length: %d <<<%s>>>\n",
length($phrase), $phrase,
charinfo(ord $char)->{'name'},
$phrase ne $squeeze ? 'True' : 'False',
length($squeeze), $squeeze
}
Output:
Original length: 0 <<<>>>
Squeezable on "SPACE": False
Squeezed length: 0 <<<>>>

Original length: 72 <<<"If I were two-faced, would I be wearing this one?" --- Abraham Lincoln >>>
Squeezable on "HYPHEN-MINUS": True
Squeezed length: 70 <<<"If I were two-faced, would I be wearing this one?" - Abraham Lincoln >>>

Original length: 72 <<<..1111111111111111111111111111111111111111111111111111111111111117777888>>>
Squeezable on "DIGIT SEVEN": True
Squeezed length: 69 <<<..1111111111111111111111111111111111111111111111111111111111111117888>>>

Original length: 72 <<<I never give 'em hell, I just tell the truth, and they think it's hell. >>>
Squeezable on "FULL STOP": False
Squeezed length: 72 <<<I never give 'em hell, I just tell the truth, and they think it's hell. >>>

Original length: 72 <<<                                                    --- Harry S Truman  >>>
Squeezable on "SPACE": True
Squeezed length: 20 <<< --- Harry S Truman >>>

Original length: 72 <<<                                                    --- Harry S Truman  >>>
Squeezable on "HYPHEN-MINUS": True
Squeezed length: 70 <<<                                                    - Harry S Truman  >>>

Original length: 72 <<<                                                    --- Harry S Truman  >>>
Squeezable on "LATIN SMALL LETTER R": True
Squeezed length: 71 <<<                                                    --- Hary S Truman  >>>

Perl 6[edit]

Works with: Rakudo version 2019.07.1
map {
my $squeeze = $^phrase;
sink $^reg;
$squeeze ~~ s:g/($reg)$0+/$0/;
printf "\nOriginal length: %d <<<%s>>>\nSqueezable on \"%s\": %s\nSqueezed length: %d <<<%s>>>\n",
$phrase.chars, $phrase, $reg.uniname, $phrase ne $squeeze, $squeeze.chars, $squeeze
},
'', ' ',
'"If I were two-faced, would I be wearing this one?" --- Abraham Lincoln ', '-',
'..1111111111111111111111111111111111111111111111111111111111111117777888', '7',
"I never give 'em hell, I just tell the truth, and they think it's hell. ", '.',
' --- Harry S Truman ', ' ',
' --- Harry S Truman ', '-',
' --- Harry S Truman ', 'r'
Output:
Original length: 0 <<<>>>
Squeezable on "SPACE": False
Squeezed length: 0 <<<>>>

Original length: 72 <<<"If I were two-faced, would I be wearing this one?" --- Abraham Lincoln >>>
Squeezable on "HYPHEN-MINUS": True
Squeezed length: 70 <<<"If I were two-faced, would I be wearing this one?" - Abraham Lincoln >>>

Original length: 72 <<<..1111111111111111111111111111111111111111111111111111111111111117777888>>>
Squeezable on "DIGIT SEVEN": True
Squeezed length: 69 <<<..1111111111111111111111111111111111111111111111111111111111111117888>>>

Original length: 72 <<<I never give 'em hell, I just tell the truth, and they think it's hell. >>>
Squeezable on "FULL STOP": False
Squeezed length: 72 <<<I never give 'em hell, I just tell the truth, and they think it's hell. >>>

Original length: 72 <<<                                                    --- Harry S Truman  >>>
Squeezable on "SPACE": True
Squeezed length: 20 <<< --- Harry S Truman >>>

Original length: 72 <<<                                                    --- Harry S Truman  >>>
Squeezable on "HYPHEN-MINUS": True
Squeezed length: 70 <<<                                                    - Harry S Truman  >>>

Original length: 72 <<<                                                    --- Harry S Truman  >>>
Squeezable on "LATIN SMALL LETTER R": True
Squeezed length: 71 <<<                                                    --- Hary S Truman  >>>

Phix[edit]

constant tests = {"",                                                                         " ",
`"If I were two-faced, would I be wearing this one?" --- Abraham Lincoln `,"-",
"..1111111111111111111111111111111111111111111111111111111111111117777888","7",
"I never give 'em hell, I just tell the truth, and they think it's hell. ",".",
" --- Harry S Truman "," -r"},
fmt = """
length %2d input: <<<%s>>>
length %2d squeeze(%c): <<<%s>>>
"""
function squeeze(sequence s, integer ch)
if length(s)>1 then
integer outdx = 1
object prev = s[1]
for i=2 to length(s) do
if s[i]!=prev or prev!=ch then
prev = s[i]
outdx += 1
s[outdx] = prev
end if
end for
s = s[1..outdx]
end if
return s
end function
 
for i=1 to length(tests) by 2 do
string ti = tests[i], chars = tests[i+1]
for j=1 to length(chars) do
string si = squeeze(ti,chars[j])
printf(1,fmt,{length(ti),ti,length(si),chars[j],si})
end for
end for
Output:
length  0      input: <<<>>>
length  0 squeeze( ): <<<>>>

length 72      input: <<<"If I were two-faced, would I be wearing this one?" --- Abraham Lincoln >>>
length 70 squeeze(-): <<<"If I were two-faced, would I be wearing this one?" - Abraham Lincoln >>>

length 72      input: <<<..1111111111111111111111111111111111111111111111111111111111111117777888>>>
length 69 squeeze(7): <<<..1111111111111111111111111111111111111111111111111111111111111117888>>>

length 72      input: <<<I never give 'em hell, I just tell the truth, and they think it's hell. >>>
length 72 squeeze(.): <<<I never give 'em hell, I just tell the truth, and they think it's hell. >>>

length 72      input: <<<                                                    --- Harry S Truman  >>>
length 20 squeeze( ): <<< --- Harry S Truman >>>

length 72      input: <<<                                                    --- Harry S Truman  >>>
length 70 squeeze(-): <<<                                                    - Harry S Truman  >>>

length 72      input: <<<                                                    --- Harry S Truman  >>>
length 71 squeeze(r): <<<                                                    --- Hary S Truman  >>>

Python[edit]

from itertools import groupby
 
def squeezer(s, txt):
return ''.join(item if item == s else ''.join(grp)
for item, grp in groupby(txt))
 
if __name__ == '__main__':
strings = [
"",
'"If I were two-faced, would I be wearing this one?" --- Abraham Lincoln ',
"..1111111111111111111111111111111111111111111111111111111111111117777888",
"I never give 'em hell, I just tell the truth, and they think it's hell. ",
" --- Harry S Truman ",
"The better the 4-wheel drive, the further you'll be from help when ya get stuck!",
"headmistressship",
"aardvark",
"😍😀🙌💃😍😍😍🙌",
]
squeezers = ' ,-,7,., -r,e,s,a,😍'.split(',')
for txt, chars in zip(strings, squeezers):
this = "Original"
print(f"\n{this:14} Size: {len(txt)} «««{txt}»»»" )
for ch in chars:
this = f"Squeezer '{ch}'"
sqz = squeezer(ch, txt)
print(f"{this:>14} Size: {len(sqz)} «««{sqz}»»»" )
Output:
Original       Size: 0 «««»»»
  Squeezer ' ' Size: 0 «««»»»

Original       Size: 72 «««"If I were two-faced, would I be wearing this one?" --- Abraham Lincoln »»»
  Squeezer '-' Size: 70 «««"If I were two-faced, would I be wearing this one?" - Abraham Lincoln »»»

Original       Size: 72 «««..1111111111111111111111111111111111111111111111111111111111111117777888»»»
  Squeezer '7' Size: 69 «««..1111111111111111111111111111111111111111111111111111111111111117888»»»

Original       Size: 72 «««I never give 'em hell, I just tell the truth, and they think it's hell. »»»
  Squeezer '.' Size: 72 «««I never give 'em hell, I just tell the truth, and they think it's hell. »»»

Original       Size: 72 «««                                                   ---  Harry S Truman  »»»
  Squeezer ' ' Size: 20 ««« --- Harry S Truman »»»
  Squeezer '-' Size: 70 «««                                                   -  Harry S Truman  »»»
  Squeezer 'r' Size: 71 «««                                                   ---  Hary S Truman  »»»

Original       Size: 80 «««The better the 4-wheel drive, the further you'll be from help when ya get stuck!»»»
  Squeezer 'e' Size: 79 «««The better the 4-whel drive, the further you'll be from help when ya get stuck!»»»

Original       Size: 16 «««headmistressship»»»
  Squeezer 's' Size: 14 «««headmistreship»»»

Original       Size: 8 «««aardvark»»»
  Squeezer 'a' Size: 7 «««ardvark»»»

Original       Size: 8 «««😍😀🙌💃😍😍😍🙌»»»
  Squeezer '😍' Size: 6 «««😍😀🙌💃😍🙌»»»

REXX[edit]

/*REXX program "squeezes" all immediately repeated characters in a string (or strings). */
@.= /*define a default for the @. array. */
#.1= ' '; @.1=
#.2= '-'; @.2= '"If I were two-faced, would I be wearing this one?" --- Abraham Lincoln '
#.3= '7'; @.3= ..1111111111111111111111111111111111111111111111111111111111111117777888
#.4= . ; @.4= "I never give 'em hell, I just tell the truth, and they think it's hell. "
#.5= ' '; @.5= ' --- Harry S Truman '
#.6= '-'; @.6= @.5
#.7= 'r'; @.7= @.5
 
do j=1; L= length(@.j) /*obtain the length of an array element*/
say copies('═', 105) /*show a separator line between outputs*/
if j>1 & L==0 then leave /*if arg is null and J>1, then leave. */
say ' specified immediate repeatable character=' #.j " ('"c2x(#.j)"'x)"
say ' length='right(L, 3) " input=«««" || @.j || '»»»'
new= squeeze(@.j, #.j)
w= length(new)
say ' length='right(w, 3) " output=«««" || new || '»»»'
end /*j*/
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
squeeze: procedure; parse arg y 1 $ 2,z /*get string; get immed. repeated char.*/
if pos(z || z, y)==0 then return y /*No repeated immediate char? Return Y*/
/* [↑] Not really needed; a speed─up.*/
do k=2 to length(y) /*traipse through almost all the chars.*/
_= substr(y, k, 1) /*pick a character from Y */
if _==right($, 1) & _==z then iterate /*Same character? Skip it.*/
$= $ || _ /*append char., it's diff. */
end /*j*/
return $
output   when using the internal default inputs:
═════════════════════════════════════════════════════════════════════════════════════════════════════════
    specified immediate repeatable character=      ('20'x)
    length=  0    input=«««»»»
    length=  0   output=«««»»»
═════════════════════════════════════════════════════════════════════════════════════════════════════════
    specified immediate repeatable character= -    ('2D'x)
    length= 72    input=«««"If I were two-faced, would I be wearing this one?" --- Abraham Lincoln »»»
    length= 70   output=«««"If I were two-faced, would I be wearing this one?" - Abraham Lincoln »»»
═════════════════════════════════════════════════════════════════════════════════════════════════════════
    specified immediate repeatable character= 7    ('37'x)
    length= 72    input=«««..1111111111111111111111111111111111111111111111111111111111111117777888»»»
    length= 69   output=«««..1111111111111111111111111111111111111111111111111111111111111117888»»»
═════════════════════════════════════════════════════════════════════════════════════════════════════════
    specified immediate repeatable character= .    ('2E'x)
    length= 72    input=«««I never give 'em hell, I just tell the truth, and they think it's hell. »»»
    length= 72   output=«««I never give 'em hell, I just tell the truth, and they think it's hell. »»»
═════════════════════════════════════════════════════════════════════════════════════════════════════════
    specified immediate repeatable character=      ('20'x)
    length= 72    input=«««                                                   ---  Harry S Truman  »»»
    length= 20   output=««« --- Harry S Truman »»»
═════════════════════════════════════════════════════════════════════════════════════════════════════════
    specified immediate repeatable character= -    ('2D'x)
    length= 72    input=«««                                                   ---  Harry S Truman  »»»
    length= 70   output=«««                                                   -  Harry S Truman  »»»
═════════════════════════════════════════════════════════════════════════════════════════════════════════
    specified immediate repeatable character= r    ('72'x)
    length= 72    input=«««                                                   ---  Harry S Truman  »»»
    length= 71   output=«««                                                   ---  Hary S Truman  »»»
═════════════════════════════════════════════════════════════════════════════════════════════════════════

Tcl[edit]

# Set test data as a list pairing even and odd values
# as test string and squeeze character(s) respectively.
set test {
{} {" "}
{"If I were two-faced, would I be wearing this one?" --- Abraham Lincoln } {"-"}
{..1111111111111111111111111111111111111111111111111111111111111117777888} {"7"}
{I never give 'em hell, I just tell the truth, and they think it's hell. } {"."} ;# '
{ --- Harry S Truman } {" " "-" "r"}
{The better the 4-wheel drive, the further you'll be from help when ya get stuck!} {"e"} ;# '
{headmistressship} {"s"}
}
 
foreach {str chrs} $test {
foreach c $chrs {
# Escape non-word replacement characters (such as .)
set c [regsub -all {\W} $c {\\&}]
 
# Uses regexp lookbehind to detect repeated characters
set re [subst -noback {($c)(\1+)}] ;# build expression
set sub [regsub -all $re $str {\1}]
 
# Output
puts [format "Original (length %3d): %s" [string length $str] $str]
puts [format "Subbed (length %3d): %s" [string length $sub] $sub]
puts ----------------------
}
}
 
 
Output:
Original (length   0):
Subbed   (length   0):
----------------------
Original (length  72): "If I were two-faced, would I be wearing this one?" --- Abraham Lincoln
Subbed   (length  70): "If I were two-faced, would I be wearing this one?" - Abraham Lincoln
----------------------
Original (length  72): ..1111111111111111111111111111111111111111111111111111111111111117777888
Subbed   (length  69): ..1111111111111111111111111111111111111111111111111111111111111117888
----------------------
Original (length  72): I never give 'em hell, I just tell the truth, and they think it's hell.
Subbed   (length  72): I never give 'em hell, I just tell the truth, and they think it's hell.
----------------------
Original (length  72):                                                     --- Harry S Truman
Subbed   (length  20):  --- Harry S Truman
----------------------
Original (length  72):                                                     --- Harry S Truman
Subbed   (length  70):                                                     - Harry S Truman
----------------------
Original (length  72):                                                     --- Harry S Truman
Subbed   (length  71):                                                     --- Hary S Truman
----------------------
Original (length  80): The better the 4-wheel drive, the further you'll be from help when ya get stuck!
Subbed   (length  79): The better the 4-whel drive, the further you'll be from help when ya get stuck!
----------------------
Original (length  16): headmistressship
Subbed   (length  14): headmistreship
----------------------

zkl[edit]

fcn squeeze(c,str){	// Works with UTF-8
s,cc,sz,n := Data(Void,str), String(c,c), c.len(), 0; // byte buffer in case of LOTs of deletes
while(Void != (n=s.find(cc,n))){ str=s.del(n,sz) } // and searching is faster for big strings
s.text
}
strings:=T(
T("",""),
T("-","\"If I were two-faced, would I be wearing this one?\" --- Abraham Lincoln "),
T("7","..1111111111111111111111111111111111111111111111111111111111111117777888"),
T(" ","I never give 'em hell, I just tell the truth, and they think it's hell. "),
T(" "," --- Harry S Truman "),
T("-"," --- Harry S Truman "),
T("r"," --- Harry S Truman "),
T("e","The better the 4-wheel drive, the further you'll be from help when ya get stuck!"),
T("s","headmistressship"),
T("\Ubd;","\Ubc;\Ubd;\Ubd;\Ube;"),
);
 
foreach c,s in (strings){
println("Squeeze: \"",c,"\"");
println("Before: %2d <<<%s>>>".fmt(s.len(-8),s));
sstr:=squeeze(c,s);
println("After:  %2d <<<%s>>>\n".fmt(sstr.len(-8),sstr));
}
Output:
Squeeze: ""
Before:  0 <<<>>>
After:   0 <<<>>>

Squeeze: "-"
Before: 72 <<<"If I were two-faced, would I be wearing this one?" --- Abraham Lincoln >>>
After:  70 <<<"If I were two-faced, would I be wearing this one?" - Abraham Lincoln >>>

Squeeze: "7"
Before: 72 <<<..1111111111111111111111111111111111111111111111111111111111111117777888>>>
After:  69 <<<..1111111111111111111111111111111111111111111111111111111111111117888>>>

Squeeze: " "
Before: 72 <<<I never give 'em hell, I just tell the truth, and they think it's hell. >>>
After:  72 <<<I never give 'em hell, I just tell the truth, and they think it's hell. >>>

Squeeze: " "
Before: 72 <<<                                                    --- Harry S Truman  >>>
After:  20 <<< --- Harry S Truman >>>

Squeeze: "-"
Before: 72 <<<                                                    --- Harry S Truman  >>>
After:  70 <<<                                                    - Harry S Truman  >>>

Squeeze: "r"
Before: 72 <<<                                                   ---  Harry S Truman  >>>
After:  71 <<<                                                   ---  Hary S Truman  >>>

Squeeze: "e"
Before: 80 <<<The better the 4-wheel drive, the further you'll be from help when ya get stuck!>>>
After:  79 <<<The better the 4-whel drive, the further you'll be from help when ya get stuck!>>>

Squeeze: "s"
Before: 16 <<<headmistressship>>>
After:  14 <<<headmistreship>>>

Squeeze: "½"
Before:  4 <<<¼½½¾>>>
After:   3 <<<¼½¾>>>