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Re: Getting the intersection of n collections.

by lima1 (Curate)
on Oct 11, 2006 at 12:10 UTC ( #577594=note: print w/ replies, xml ) Need Help??

in reply to Getting the intersection of n collections.

If the array may NOT have the same value multiple times, then this (intersect is taken and slightly modified from the perl cookbook-one must be careful these days ;) ) should work:

my @a = ( [ 1,2,3,4,5] , [2,3,6,7,8,9,10], [5,6,2,3], ); my @b = @{$a[0]}; sub intersect{ my (%union, %isect); foreach my $e (@_) { $union{$e}++ && $isect{$e}++ } return keys %isect } foreach my $a_ref (@a) { @b = intersect(@$a_ref, @b); }
UPDATE: only works for unduplicated items!

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