my @data;
    while(  <DATA>  ) {
        chomp;
        my( $num, $name )= split /\s*,\s*/, $_, 1;
        push @{$data[$num]}, $name;
    }
    my $num= 0;
    for my $byNum (  @data  ) {
        for my $name (  @$byNum  ) {
            print "$num,$name\n";
        }
        $num++;
    }

##</code><code>##

    for my $byNum (  @data  ) {
        @$byNum= sort @$byNum;
    }