Get the intersection of two lists of strings in Perl

Question

In Chapter 4, Section 4.8 (Computing Union, Intersection, or Difference of Unique Lists), the Perl Cookbook provides this technique for getting the intersection of two lists

Answer 1

Array::Utils is what you're looking for.

use Array::Utils qw(:all);

my @a = qw( a b c d );
my @b = qw( c d e f );

my @isect = intersect(@a, @b);
print join(",",@isect) . "\n";

This produces the expected output of

c,d

Edit: I didn't notice that you wanted this done case-insensitively. In that case, you can replace @a with map{lc}@a (and likewise with @b).