in reply to Sorting a hash of hashes

If your trying to sort by the first three chars of the key, then you need only to substr the key 

my @key_hash = sort {
    substr($a,3) cmp substr($b,3)
} keys %key_hash;

[download]

If your trying to sort by the first 3 chars of the value, you need to apply the substr to the value 

my @key_hash = sort {
    substr($key_hash{$a},3) cmp substr($key_hash{$b},3)
} keys %key_hash;

[download]
Examine what is said, not who speaks.
1) When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.
2) The only way of discovering the limits of the possible is to venture a little way past them into the impossible
3) Any sufficiently advanced technology is indistinguishable from magic.
Arthur C. Clarke.

In Section Seekers of Perl Wisdom