my @ary1 = ( 1..10 ); my @ary2 = ( 5..15 ); my %h; $h{$_}++ for ( @ary1, @ary2 ); unique( "Only in ary1", \@ary1, \%h ); unique( "Only in ary2", \@ary2, \%h ); common( "Common to ary1 and ary2", \%h ); sub unique { my ( $text, $ary, $hash ) = @_; print $text, $/; do{ print "$_\n" unless $hash->{$_} == 2} for @$ary; } sub common { my ( $text, $hash ) = @_; print $text, $/; do{ print "$_\n" if $hash->{$_} == 2} for keys %$hash }