The lingo for your desired operation is the difference of two arrays. This has already been answerd in How can I find the union/difference/intersection of two arrays?. Here's another solution which doesn't use a set hash: 
@a_minus_b = grep { my $a = $_; not grep { $a eq $_ } @b } @a;

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In reply to Re: How do I pick anything that is in array A that is NOT in array B by Anonymous Monk
in thread How do I pick anything that is in array A that is NOT in array B by Anonymous Monk

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