http://www.perlmonks.org?node_id=280791


in reply to Re: Re: Perl Idioms Explained - keys %{{map{$_=>1}@list}}
in thread Perl Idioms Explained - keys %{{map{$_=>1}@list}}

Adding 
'keys_map_undef' => sub { my @uniq = keys %{{ map {$_ => undef} @list 
+}}; },

[download]
to test the undef suggestion, it turns out to be 15-20% faster than using 1.

grep still wins, though.
--
Mike

In Section Meditations