Monks,

I've been kicking around a sort routine for fun: 

@sorted_by_ip = sort {
    my @a = $a->{ip} =~ /(\d+)\.(\d+)\.(\d+)\.(\d+)/;
    my @b = $b->{ip} =~ /(\d+)\.(\d+)\.(\d+)\.(\d+)/;
    
    $a[0] <=> $b[0] || 
    $a[1] <=> $b[1] || 
    $a[2] <=> $b[2] || 
    $a[3] <=> $b[3] ||
    $a->{date} cmp $b->{date} ||
    $a->{time} cmp $b->{time} 
    } @ip_date_time;

[download]
The above code sorts an array of hash containg 3 elements in the following order: IP address, Date, Time. It sorts approx. 17,000 entries. I benchmarked this sucker and it weighed in at a whopping 2 min. 38 sec. for one iteration. Then, on Benchmarking your code's suggestion, I changed
$a->{time} cmp $b->{time}
to
$a->{time} <=> $b->{time} (simply changed the comparator operator) and the time to execute dropped down to just 3 seconds! That's over 50 times faster!

So there is my Perl epiphany for the day. If anyone knows, I'd love to hear why it made such a huge difference in this particular case. I can only vaguely guess why.

$PM = "Perl Monk's";
$MCF = "Most Clueless Friar Abbot";
$nysus = $PM . $MCF;
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In reply to Speeding up sort routines by nysus

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