Hi, the classic technique is to put the elements of one array into a hash and see if the elements of the other array have keys in the hash.

Update: Here's an example, with some points to consider:

• Always use strict and warnings. Whoever showed you Perl for the first time should be beaten for not telling you that.
• Declare your variables with my to keep them under control.
• Use map to quickly loop through an list if you want to use the loop to make another list.
• A hash is a type of array, so can be built with map by alternating keys and values.
• When you use for or foreach, Perl will handle exiting the loop when the list is empty.
• You can use if in the traditional way with braces, or as a postfix condition.

use strict;
use warnings;
use feature 'say';

my @array1 = ("A2","A5","C1","G0","T3","T4");
my @array2 = ("A2","A3","A5","G1","G0","G4");

my %lookup = map { $_ => 1 } @array1;

for my $thing ( @array2 ) {
    say "I found $thing" if $lookup{ $thing };
}

__END__
[download]

Hope this helps!



The way forward always starts with a minimal test.

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