A X B Y C Z D X E X #### use strict; use warnings; open(IN, "list.txt") or die; chomp($line = ); ($a, @ss) = split /\s+/, $line; while (chomp($line = )) { ($aa, @prs) = split /\s+/, $line; for ($i=0; $i<@prs; $i++) { $s{$aa}{$ss[$i]} = $prs[$i]; } } close(IN); #### A B C D A 0 0 0 0 B 0 2 2 0 C 0 2 2 0