#!/your/perl/here use strict; use warnings; my @array1 = qw(dog cat rat mouse); my @array2 = qw(dog rat mouse bird); my @array3 = qw(cat rat fish mouse); my %seen; my @collection; foreach my $item ( @array1, @array2, @array3 ) { unless ( exists( $seen{$item} ) ) { push @collection, $item; $seen{$item}++; } } print "@collection\n"; __END__