Perl regular expression named groups array

Question

I'm trying to capture named groups in an array.

use strict;
use warnings;
use Data::Dumper;

my $text = 'My aunt is on vacation and eating some apples and banana';
$text =~ m/(?<Letter>A.)/img ;
print Dumper(%-) ;

output is

$VAR1 = 'Letter';
$VAR2 = [
          'au'
        ];

but I would expect or actually was hoping that any occurrence will appear in the array.

$VAR1 = 'Letter';
$VAR2 = [
          'au',
          'ac',
          'at',
          'an',
          'at',
          'an'
        ];

Any chance to get all groups in one array?

choroba · Accepted Answer · 2022-10-03 17:05:32Z

3

You can either run the m//g in list context to get all the matching substrings (but without the capture names), or you need to match in a loop:

my @matches = $text =~ m/(?<Letter>A.)/img ;
print Dumper(\@matches) ;

or

while ($text =~ m/(?<Letter>A.)/img) {
       print Dumper(\%+) ;
}

answered Oct 3, 2022 at 17:05

choroba

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4 Comments

ssr1012 Over a year ago

Champion: what a magic in this code +1. How its printing with letter 'Letter' => 'an' Could you please explain the second code?

choroba Over a year ago

%- is needed when there are several groups of the same name. %+ is simpler when there's only one group per name. Using a reference (i.e. \) in Dumper for a hash or array prints the structure rather than printing individual values (or keys and values).

EricStolz Over a year ago

But if %- is capturing multiple groups of same name and giving an array for what do I need to run with foreach over it again. Confusing and not logical to me. But thanks for you answer. Will create a function retuning the array I require.

choroba Over a year ago

@EricStolz: %- is for cases like /a(?<letter>.).*?a(?<letter>.)/, where the same named capture group appears several times in the regex, not when it matches several times. The latter case must be solved with a loop.

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