How do I search a Perl array for a matching string?

Question

What is the smartest way of searching through an array of strings for a matching string in Perl?

One caveat, I would like the search to be case-insensitive

so "aAa" would be in ("aaa","bbb")

Answer 1

It depends on what you want the search to do:

• if you want to find all matches, use the built-in grep:

  my @matches = grep { /pattern/ } @list_of_strings; 

• if you want to find the first match, use first in List::Util:

  use List::Util 'first';   my $match = first { /pattern/ } @list_of_strings; 

• if you want to find the count of all matches, use true in List::MoreUtils:

  use List::MoreUtils 'true'; my $count = true { /pattern/ } @list_of_strings; 

• if you want to know the index of the first match, use first_index in List::MoreUtils:

  use List::MoreUtils 'first_index';  my $index = first_index { /pattern/ } @list_of_strings; 

• if you want to simply know if there was a match, but you don't care which element it was or its value, use any in List::Util:

  use List::Util 1.33 'any'; my $match_found = any { /pattern/ } @list_of_strings; 

All these examples do similar things at their core, but their implementations have been heavily optimized to be fast, and will be faster than any pure-perl implementation that you might write yourself with grep, map or a for loop.

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Note that the algorithm for doing the looping is a separate issue than performing the individual matches. To match a string case-insensitively, you can simply use the i flag in the pattern: /pattern/i. You should definitely read through perldoc perlre if you have not previously done so.

Answer 2

I guess

@foo = ("aAa", "bbb"); @bar = grep(/^aaa/i, @foo); print join ",",@bar; 

would do the trick.