Re^2: Generating a list of numbers from other lists

[mbethke]

To avoid the expensive split in a sort block, you could separate the results in lists of their own using a second hash:

my (%result, %sums);
while (<DATA>) {
    chomp;
    my ($first, $second) = split;

    if ($numberHash{$first}) {
        push @{$result{$first}}, $second;
        $sums{$first}+= $second;
    }
}

foreach my $first (sort { $a <=> $b } keys %result) {
    foreach my $second (@{$result{$first}}) {
        print "$first $second $sums{$first}\n";
    }
}

Just in case the OP ever wants to process tens of megabytes that way :)

[Marshall]

I certainly appreciate your point! And it is well taken.

I try to modulate my response to the skill level reflected by the original question (with an imperfect heuristic). Sometimes I am more effective at this than at other times. The HoA (Hash of Array) syntax can often be a bit confusing for beginners. I just avoided this "what heck does push @{$result{$first}}"? mean by not doing that. Anyway, I think the collective "Monk Wisdom" has done well for this OP - there a several alternatives, all of which will probably work out just fine.