Re: Perl regular expression question

In addition to the very helpful comments you've already received, I'd like to point out that, as a rule, I'd "metaquote" the scalar variable in the regex, just in case it contains characters (e.g. +) that otherwise would have special meaning in a regular expression:

m|\Q$input|o
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For example:

my $string = '15+2=17';
my $input  = '5+2';
$string =~ m|$input|o;    # Fails
$string =~ m|\Q$input|o;  # Succeeds
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The first match fails because it tries to match one or more 5s immediately followed by a 2. That's because the + is being interpreted as a regexp quantifier, not a literal character.

See the aforementioned perlre, and while you're at it also check out quotemeta.

the lowliest monk

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Re^2: Perl regular expression question by halley (Prior) on Aug 25, 2005 at 13:21 UTC
Unless of course $input were a stored regular expression (such as `qr//`), where the matching behavior was expressly desired. -- `[ e d @ h a l l e y . c c ]`	[reply] [d/l]