my @third_fragments = grep -v ($rsite3), $second_fragments[$i] my @final_fragment1 = $seqname."_".$i."_1"; my @final_fragment2 = $seqname."_".$i."_2"; $final_fragments{$final_fragment1} = $third_fragments[0]; $final_fragments{$final_fragment2} = $third_fragments[scalar @third_fragments - 1];