I am really bad in regex and my best attempt that is working from my point of view is really poor in syntax. I am sure that it can be done in a different way and shorter.

I am currently having a string that it is 24 numerical characters long and I have created a regex to split the string on pieces character by character so I can extract the odd place holders that contain the actual information that I need.

What I have so far is:

#!/usr/bin/env perl
use strict;
use warnings;

my $sample = "041424344454647484940414";
$sample =~ /([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([
+0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])(
+[0-9])([0-9])([0-9])([0-9])([0-9])([0-9])/; # 24 times the same patte
+rn
print "$1$3$5$7$9$11$13$15$17$19$21$23\n";

__END__
$ perl test.pl
012345678901
[download]

This is the desired output and it is working but I was wondering if there is a more elegant way to minimize replicating the same group 24 times but also being able to get the odd place holders ($1$3$5...).

I could use potentially split the string character by character and store the output in an array. Where from there I would remove the even elements and reform the array into string with join. But in my case this is not possible as the system that I am writing the regex does not support the split function or join it only supports C format commands syntax, so I am using Perl as a test tool before implementation.

If any one has any idea how to make this regex shorter feel free to drop a comment.

Thanks in advance for your time and effort, BR.