Greetings all,
Update
After re-reading the OP I have modified the following code to only identify those elements that are not unique to only one list and are not found in all lists.
This has the benefit of not hard-coding in '2' as a comparison since this logic may need to be extended to more lists in the future.
my @a1 = qw(1 2 5 9 11 12 13);
my @a2 = qw(1 2 5 11 12 13);
my @a3 = qw(1 2 5 7 9 12 13);

my @shared = shared(\@a1, \@a2, \@a3);

sub shared
{
    my $lim = scalar(@_);
    my @lists = map{@{$_}}@_;
    return do{my %seen;
        $seen{$_}++ for(@lists);
        map{delete $seen{$_} if($seen{$_} == 1 || $seen{$_} == $lim)}k
+eys %seen;
        sort {$a <=> $b} keys %seen;
    };
}

[download]

Output is
9 11

[download]


-InjunJoel
"I do not feel obliged to believe that the same God who endowed us with sense, reason and intellect has intended us to forego their use." -Galileo

In reply to Re: array comparison question by injunjoel
in thread array comparison question by Anonymous Monk

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