I personally like the hash of arrays approach, as it more closely mirrors the way I think about the problem: a key (IP address) that can have one or more aliases. However, as I noted in my original post, it is not the most efficient way to do things...just a bit easier to understand for a beginner IMHO.
I understand what you're saying, but I'd go in a different direction.

If a beginner understands AoA: 

$array[$row][$col] = $pixel;

[download]
and that hashes are sort of arrays with different brackets: 
$array{$row}{$col} = $pixel;

[download]
then it's a small leap to suggest that (here, at least) the keys are the interesting bits, and the values don't matter: 
$hosts{$ip}{$alias} = 1;

[download]

-QM
--
Quantum Mechanics: The dreams stuff is made of

In reply to Re^5: Perl and arrays of arrays? by QM
in thread Perl and arrays of arrays? by Anonymous Monk

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