Failed match not stored

BillKSmith has asked for the wisdom of the Perl Monks concerning the following question:

The match operator returns an (unspecified)false value when the match fails. Why is that value not stored in this case?

use strict;
use warnings;
use version '5.38';
use feature 'say';
use Test::More tests=>1;

my @arry1 = ('string'=~ m/str/, 'second');
my @arry2 = ('string'=~ m/foo/, 'second');
# no value stored for failed match.
is $arry2[1], $arry1[1];
[download]

RESULT

not ok 1
#   Failed test at tryit2.pl line 10
#          got: undef
#     expected: 'second'
# Looks like you failed 1 test of 1.
[download]

Bill

Comment on Failed match not stored Select or Download Code

Replies are listed 'Best First'.
Re: Failed match not stored by jwkrahn (Abbot) on Apr 07, 2025 at 20:29 UTC
In list context a failed match returns an empty list. Naked blocks are fun! -- Randal L. Schwartz, Perl hacker	[reply]
Re^2: Failed match not stored by BillKSmith (Monsignor) on Apr 08, 2025 at 13:42 UTC
Thanks for the simple answer. The original problem was more subtle than my example, but in both cases, I failed to recognize the list context. Bill	[reply]
Re: Failed match not stored by duelafn (Parson) on Apr 08, 2025 at 00:09 UTC
Thus, you can fix the issue in a couple ways. Explicitly forcing scalar context: `use Test::More tests=>1; my @arry1 = (scalar 'string' =~ m/str/, 'second'); my @arry2 = (scalar 'string' =~ m/foo/, 'second'); is $arry2[1], $arry1[1];` [download] or choosing your false value (and implicitly forcing scalar context) `use Test::More tests=>1; my @arry1 = (('string' =~ m/str/ or 0), 'second'); my @arry2 = (('string' =~ m/foo/ or 0), 'second'); is $arry2[1], $arry1[1];` [download] Good Day, Dean	[reply] [d/l] [select]
Re^2: Failed match not stored by BillKSmith (Monsignor) on Apr 08, 2025 at 13:55 UTC
I already had a 'workaround' similar to your second solution. I will adopt your first suggestion because it explicitly addresses the real issue rather than working around it. Bill	[reply]