Also using a hash but in a different way: 

use strict;
use warnings;

my @strings = qw( 12-12 12-12-12 12-13-12-13 12-12-13-13 12-13-13-14 )
+;
 
for (@strings) {
  my %hash;
  s/(\-?)(\d\d)/ $hash{$2}++ ? '' : $1.$2 /ge;
  print "$_\n";
}

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In reply to Re: How can I reduce this with a REGEX? by hdb
in thread How can I reduce this with a REGEX? by misterperl

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