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Answer: How do I match for several strings, matching the longest string first?

by btrott (Parson)
on Apr 16, 2000 at 22:14 UTC ( #7770=categorized answer: print w/replies, xml ) Need Help??

Q&A > regular expressions > How do I match for several strings, matching the longest stringfirst? - Answer contributed by btrott

I think a good solution would be to sort the terms that you're matching for and create a regexp of the strings in sorted order. Sort them so that the regexp tries to match the longest string first, then moves on down in length until it's trying to match the shortest one.

Something like the following should work:

my @terms = ('lymph', 'lymph node'); my @text = ('right lymph node', 'lymph fluid'); # create a regexp that will match the longest # string first and capture the string that matched my $words = '\b(' . join('|', sort { length $b <=> length $a } @terms) . ')\b'; for my $text (@text) { if ($text =~ /$words/) { print $text, ": matched => ", $1, "\n"; } }

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