The solution fails because the replace operator is potentially called more than once by the while loop.

The solution seems to work with or without the while, either way producing identical results. (I changed the 2s to 7s as the 2s were difficult to spot.)

use strict;
use warnings;

my $toTranslate
   = q{3333333333773333377}; # 19
#      .........1....1....
#      ....5....0....5....
print qq{Sequences of 3s:-\n};
print qq{[@{ [ length $1 ] }]\n}
   while $toTranslate =~ m{(3+)}g;

( my $translated = $toTranslate )
   =~ s{((?:3{4})+)}{ qq{[@{ [ length $1 ] }]} }eg;
print qq{@{ [ q{-} x 50 ] }\n$translated\n@{ [ q{-} x 50 ] }\n};

1 while $toTranslate =~ s{((?:3{4})+)}{ qq{[@{ [ length $1 ] }]} }eg;
print qq{$toTranslate\n@{ [ q{=} x 50 ] }\n};

$toTranslate
   = q{3333333333333333333333333} # 25
   . q{3333333333333333333333333} # 50
   . q{3333333333333333333333333} # 75
   . q{3333333333333333333333333} # 100
   . q{3333333333333333373333333} # 125
   . q{3377333333333733333333333} # 150
   . q{3333333333333333333333733} # 175
   . q{3333337733333333733333333} # 200
   . q{3};                        # 201
#      .........1....1....2....2
#      ....5....0....5....0....5
print qq{Sequences of 3s:-\n};
print qq{[@{ [ length $1 ] }]\n}
   while $toTranslate =~ m{(3+)}g;

( $translated = $toTranslate )
   =~ s{((?:3{4})+)}{ qq{[@{ [ length $1 ] }]} }eg;
print qq{@{ [ q{-} x 50 ] }\n$translated\n@{ [ q{-} x 50 ] }\n};

1 while $toTranslate =~ s{((?:3{4})+)}{ qq{[@{ [ length $1 ] }]} }eg;
print qq{$toTranslate\n@{ [ q{=} x 50 ] }\n};

[download]

Produces

Sequences of 3s:-
[10]
[5]
--------------------------------------------------
[8]3377[4]377
--------------------------------------------------
[8]3377[4]377
==================================================
Sequences of 3s:-
[117]
[9]
[9]
[33]
[8]
[8]
[9]
--------------------------------------------------
[116]37[8]377[8]37[32]37[8]77[8]7[8]3
--------------------------------------------------
[116]37[8]377[8]37[32]37[8]77[8]7[8]3
==================================================

[download]

I hope this is of interest

Cheers,

JohnGG

In reply to Re^2: Regex exact pattern match problem! by johngg
in thread Regex exact pattern match problem! by Jts

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