You have to understand that the numerical variables retain their values from the last successful match and '1c' is matched by the first capturing parentheses, and '2w', '2c3w', and '1w1w' are captured by the second capturing parentheses, and '1w2r' and '2r1c' are captured by the third capturing parentheses so the values returned by the other capturing parentheses are not valid and/or undefined.   To get valid results only use the contents of the capturing parentheses that actually matched: 

use strict;
use warnings;

print "Enter your test strings:\n";
while ( <DATA> )
{
    chomp;
    print "\tTesting '$_':\n";
    /^(?:(?:(\d+)\s*c\s*)|(?:(\d+)\s*w\s*)|(?:(\d+)\s*r\s*))+/i and pr
+int "Capturing \\d+ only:             '$+'\n";
        /^(?:(?:(\d+\s*c)\s*)|(?:(\d+\s*w)\s*)|(?:(\d+\s*r)\s*))+/i an
+d print "Capturing \\d+ plus the letter:  '$+'\n";
}

__DATA__
1c
2w
2c3w
1w1w
1w2r
2r1c

[download]

In reply to Re: Leaking Regex Captures by jwkrahn
in thread Leaking Regex Captures by SuicideJunkie

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.