Of course, ++merlyns post shows what an elegant solution is... So that's the cute idiom you where asking for!

Assuming you /can|want/ not process the duplicates right away, you could save memory by omitting the extra array @out. When you go over the array for the fist time, do the counting, then do the processing separately:

my @in = qw(test foo test bar baz foo test); my %keycount; foreach (@in) { $keycount{$_}++; # do whatever else you need to do } foreach (keys %keycount) { #print $_ if $keycount > 1; print if $keycount{$_} > 1; # Thx, ++Aristotle! # or do something else with $_ }

So long,

In reply to Re: Get All Duplicated Elements in an Array (Once, without shifting) by Flexx
in thread Get All Duplicated Elements in an Array (Once, without shifting) by George_Sherston

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