my %seen;
$seen{$_}=1 for @list1;
my @intersection = grep ++$seen{}==2, @list2;

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You are missing a $_ there. And it doesn't work. (Consider @list1=(); @list2=qw(foo foo);.)
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In reply to Re^2: is there a more simple way to have the intersection of two lists ? by ysth
in thread is there a more simple way to have the intersection of two lists ? by steph_bow

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