in reply to Behavior of /g when there are capture groups

If you call the regex in scalar context (ex: as a conditional) /g will make it possible to work one match at a time, allowing you to have finer control over what you do with the captures. 

#use Data::Dumper;
my %res;
while (/(fo.)(.*?)(ba.)/g)
{
  $res{$&} = [ @-[1..3] ];
}
print Dumper \%res;

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Edit: the slice should be on indices 1..3, not 0..2.

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Re^2: Behavior of /g when there are capture groups
by AnomalousMonk (Archbishop) on Apr 21, 2016 at 19:18 UTC

    This could be generalized to extract substrings, not just substring initial offsets; also to avoid  $& which just slows everything down. (The many evals might slow things down, though. Oh, well...) (Also tested under 5.8.9.) 

    c:\@Work\Perl>perl -wMstrict -le
"use Data::Dumper;
 ;;
 $_ = 'abcdfoofrobnicatebardefforspambazghi';
 ;;
 my $re = qr{ (fo.) (.*?) (ba.) }xms;
 ;;
 my %res;
 while (/($re)/g) {
   $res{$1} = [ map eval qq{\$$_}, 2 .. $#- ];
   }
 print Dumper \%res;
"
$VAR1 = {
          'forspambaz' => [
                            'for',
                            'spam',
                            'baz'
                          ],
          'foofrobnicatebar' => [
                                  'foo',
                                  'frobnicate',
                                  'bar'
                                ]
        };

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    Give a man a fish:  <%-{-{-{-<

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      I should have tested my code, I got confused and thought @- held the submatches themselves, not the indexes. So I actually meant $res{$&} = [ $1, $2, $3]; but got lazy :). And $res{$1} = [ $2, $3, $4 ] works without $& with the extra parentheses.

      Your proposition has the benefit of not requiring to know the inner regex and its number of captures :)

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Re^2: Behavior of /g when there are capture groups
by ExReg (Priest) on Apr 21, 2016 at 15:53 UTC

    Thanks! I was unaware of that trick.

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