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Re: Extracting elements in one array but not in another

by emazep (Priest)
on Oct 23, 2004 at 06:50 UTC ( #401778=note: print w/ replies, xml ) Need Help??


in reply to Extracting elements in one array but not in another

To find elements that are in one array but not in another, there is a nice loopless solution from the Perl Cookbook which uses the delete function:

my %seen; @seen{ @original_1 } = (); delete @seen{ @original_2 }; my @original_1_only = keys %seen;
Of course there is also a loopy solution, should you prefer it:
my %seen; my @original_1_only; @seen{ @original_2 } = (); foreach (@original_1) { push(@original_1_only, $_) unless exists $seen{$_}; };
Stick with these.

Ciao,
Emanuele.


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