This is addressed in perlfaq4 at How do I compute the difference of two arrays. The code there could be adapted to your specific need pretty easily.
Here's the code from perlfaq4:
my (@union, @intersection, @difference);
my %count = ();
foreach my $element (@array1, @array2) { $count{$element}++ }
foreach my $element (keys %count) {
push @union, $element;
push @{ $count{$element} > 1 ? \@intersection : \@difference }
+, $element;
}
Here's one way to adapt it.
sub difference {
my $array_ref1 = shift;
my $array_ref2 = shift;
my @difference;
foreach my $element (@$array_ref1, @$array_ref2) { $count{$element
+}++ };
foreach my $element (keys %count) {
push @difference, $element if $count{$element} == 1;
}
return \@difference;
}
(please do test it -- this is untested code.)
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