#!/usr/bin/perl
use warnings;
use strict;

my @one = ( 1, 2, 3, 4);
my @two = ( 2, 4, 6, 8);
my (%in_one, %in_two, @in_both, @only_in_one, @only_in_two);

@in_one{ @one} = 1;
@in_two{ @two} = 1;

@in_both = grep {  exists $in_one{$_} } @two;

@only_in_one = grep { not exists $in_two{$_}} @one;
@only_in_two = grep { not exists $in_one{$_}} @two;


local $, = " ";
print "\@one         ", @one, "\n";
print "\@two         ", @two, "\n";
print "\@only_in_one ", @only_in_one, "\n";
print "\@only_in_two ", @only_in_two, "\n";
print "\@in_both     ", @in_both, "\n";

__DATA__

@one          1 2 3 4
@two          2 4 6 8
@only_in_one  1 3
@only_in_two  6 8
@in_both      2 4