foreach $row_el (@row_els) {
    print  "\t",$row_el;
    foreach $global_el (@global_els) {
        # add this line...
        next unless exists $score_of{$row_el}{$global_el};
        print  "\t",$global_el;
		print  ",",$score_of{$row_el}{$global_el};
    }
    print  "\n";
}