Determine if a string is squeezable
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
REXX
<lang rexx>/*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= ..1111111111111111111111111111111111111111111111111111111111111111177788
- .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 chararacter=' #.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 $</lang>
- output when using the internal default inputs:
═════════════════════════════════════════════════════════════════════════════════════════════════════════
specified immediate repeatable chararacter= ('20'x)
length= 0 input=«««»»»
length= 0 output=«««»»»
═════════════════════════════════════════════════════════════════════════════════════════════════════════
specified immediate repeatable chararacter= - ('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 chararacter= 7 ('37'x)
length= 72 input=«««..1111111111111111111111111111111111111111111111111111111111111111177788»»»
length= 70 output=«««..11111111111111111111111111111111111111111111111111111111111111111788»»»
═════════════════════════════════════════════════════════════════════════════════════════════════════════
specified immediate repeatable chararacter= . ('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 chararacter= ('20'x)
length= 72 input=««« --- Harry S Truman »»»
length= 20 output=««« --- Harry S Truman »»»
═════════════════════════════════════════════════════════════════════════════════════════════════════════
specified immediate repeatable chararacter= - ('2D'x)
length= 72 input=««« --- Harry S Truman »»»
length= 70 output=««« - Harry S Truman »»»
═════════════════════════════════════════════════════════════════════════════════════════════════════════
specified immediate repeatable chararacter= r ('72'x)
length= 72 input=««« --- Harry S Truman »»»
length= 71 output=««« --- Hary S Truman »»»
═════════════════════════════════════════════════════════════════════════════════════════════════════════