untested, but this should work:

my %hash;
@hash{ map { $_->[0] } @listA } = ( 1 ) x @listA;

grep{ 1 unless defined $hash{$_->[0]} } @listB;

[download]

looking up 'intersection' in the search box comes up with some useful results

In reply to Re: Trying to get fancy... by AidanLee
in thread Trying to get fancy... by Purdy

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