should it be a regex?

you can use a hash to hold the data and check if an element has occured more than once. 
my %temp;
my @captured = grep { defined $temp{$_}++ } split / /, <DATA>;

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If you need exactly two, try this 
my %temp;
my @captured = grep { ++$temp{$_} == 2 } split / /, <DATA>;

[download]
He who asks will be a fool for five minutes, but he who doesn't ask will remain a fool for life.

Chady | http://chady.net/

In reply to Re: Red Nex Needed by Chady
in thread Reg Ex Needed by Anonymous Monk

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