in reply to Tri state string compare? (Solved! see update2)

Replace all "don't care characters" with . and you have a regex that does the job. 

use strict;
use warnings;
my $abc = "AABCBAABCCCCAB";
my $ab  = "AABABAABABABAB";
$abc =~ s/[^ab]/./gi;
print "They match!\n" if $ab =~ /^$abc$/i;

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If you want to use logical operators the following works as well 

print "They match!\n" unless ($abc ^ $ab) =~ /\x{3}/;

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Re^2: Tri state string compare?
by mr_ron (Deacon) on Dec 14, 2015 at 16:09 UTC

    Just a variant that takes the rules of the original question a little more literally and strictly ...

    use strict;
use warnings;
my $abc = "AABCBAABCCCCAB";
my $ab  = "AABABAABABABAB";
$abc =~ s/C/[AB]/g;
$abc = qr/^$abc$/;
print "They match!\n" if $ab =~ $abc;

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    Ron
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