I suggest you use DB_File and have at least one hash looking like

my %ZipTo = (
95119 => 'San Jose, CA'
);
[download]

This will simplify things considerably. If you need a reverse mapping, well, just reverse the hash. You can use DB_File to match partial keys, and you can have duplicate keys.

Anyway, that's what I'd do.

____________________________________________________
** The Third rule of perl club is a statement of fact: pod is sexy.