Grr! Intersection & difference of arrays is something that ought to be in core.

Looked in List::MoreUtils to no avail.

I looked at cpan and downloaded Array::Utils but it can't handle duplicates.

Looked at List::Compare, but it comes complete with the kitchen sink & waste disposal (aliased as Belfast Sink & waste bin) and calculates 20 different things under the guise of "initalising".

Could you post an example of input array and expected outputs please.

Sure!!! If
@array = (40,17,40,30,40,25,40); is given

something like

@subarray1 = (40,40,30)
@subarray2 = (40,40,17,25)

should be returned.

I guess you already have your own sources, but for intersection of arrays I always use a function from PerlFAQ 4:


@union = @intersection = @difference = ();
    %count = ();
    foreach $element (@array1, @array2) { $count{$element}++ }
    foreach $element (keys %count) {
        push @union, $element;
        push @{ $count{$element} > 1 ? \@intersection : \@difference }
+, $element;
        }
[download]


Let me know if you need more examples, or what kind of them are you looking for

Use:

    return \@best, [ grep{ !--$seen{ $_ } <= 0 } @$aRef ];
[download]

The trouble with the FAQ is it conflates two things.

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