perl -MData::Dumper -e ' my @AoA=( ["one", "two", "three"], ["four", "five", "six"], ["four","five","six"], ["seven", "eight", "nine"], ["eight", "seven", "nine"]); my @r = grep{++$uniq{ join $; , sort @$_ } == 1 } @AoA; print "\@r is now:\n", Dumper(\@r), "\%uniq is now:\n",Dumper(\%uniq)'