Fellow Monasterians,

This one had me stumped! And while I did get it to work, I'm curious why this happens. Basically, the difference between the two examples is that the top one attempts to assign the backreference after the conditional block (returns undef) and the bottom one does it for each condition (and returns a value successfully). Question: why this behavior?

use strict;

my $string = "This is a regex test";
my ($condition, $match);

if ($condition) {
    $string =~ /(is a)/;
} else {
   $string =~ /(regex)/;
}

$match = $1;
print $match."\n";

[download]

And the winner:

if ($condition) {
   $string =~ /(is a)/;
   $match = $1;
} else {
   $string =~ /(regex)/;
   $match = $1;
}

print $match."\n";

[download]

Thanks, all!

Update: Scooped by scope again! Thanks all, I knew there had to be an explanation somewhere, as the Camel was strangely silent on the topic.


—Brad
"Don't ever take a fence down until you know the reason it was put up." G. K. Chesterton

In reply to Curious about regex capture in conditional by bradcathey

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.