You can also use a sieve. It's potentially faster than a complicated sort() algorithm to place things matching certain patterns before others.
The code you post maybe faster than a 'sort', but compared to your "sieve", the sort needed is very simple.

I fail to understand the reason of this awfully complicated code. For this case, I'd just iterate over the hash twice: 

my ($k, $v);
$v =~ /C5$/ and print "$k $v\n" while ($k, $v) = each %tapes;
$v =~ /P5$/ and print "$k $v\n" while ($k, $v) = each %tapes;

[download]
If you want to iterate once, you need additional storage: 
my (@C5, @P5);
while (my ($k, $v) = each %tapes) {
    $v =~ /C5$/ ? push @C5, "$k $v\n" 
                : push @P5, "$k $v\n";
}
print @C5, @P5;

[download]
Although you can reduce storage costs by printing the first set while iterating: 
my @P5;
while (my ($k, $v) = each %tapes) {
    $v =~ /C5$/ ? print "$k $v\n" : push @P5, "$k $v\n";
}
print @P5;

[download]
Perl --((8:>*

In reply to Re^2: Crazy hash sorting issue. by Perl Mouse
in thread Crazy hash sorting issue. by rementis

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