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Re^2: Matching Exact Word

by Jim (Curate)
on Oct 09, 2014 at 18:33 UTC ( #1103330=note: print w/replies, xml ) Need Help??

in reply to Re: Matching Exact Word
in thread Matching a Word Exactly

If what you want is to match Guinea but not New Guinea or Equatorial Guinea, then what you probably really want is a negative lookbehind assertion that specifically rules out being preceded by "New " or "Equatorial "

One caveat:  You can't use alternation in the look-behind assertion because variable-length negative look-behind assertion isn't supported. Instead, you must list the alternatives separately. You can, of course, use alternation in the look-ahead assertion.

use strict; use warnings; my $pattern = qr{ (?<!New\s) (?<!Equatorial\s) Guinea (?![\s-](?:Bissau|pig)) }ix; while (my $text = <DATA>) { my $match = $text =~ m/$pattern/ ? 1 : 0; print "$match $text"; # This prints... # 0 Papua New Guinea # 1 I live in Guinea. # 1 i live in guinea, but i don't have a shift key. # 0 Guinea-Bissau # 0 Guinea Bissau # 0 Equatorial Guinea # 0 I love guinea pigs! } __DATA__ Papua New Guinea I live in Guinea. i live in guinea, but i don't have a shift key. Guinea-Bissau Guinea Bissau Equatorial Guinea I love guinea pigs!

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