Re^3: Perl Idioms Explained - keys %{{map{$_=>1}@list}}

[Aristotle]

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

No, that won't fly. You need

$seen{$_}++ for @list;
my @doubles = grep $seen{$_} == 2, @list;

Makeshifts last the longest.