Actually, this: 

$unique_ids = scalar(grep {defined $_} @normal_array);

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will not find the number of unique IDs in @normal_array, it'll simply count how many elements of @normal_array are defined. I recommend using the uniq function from List::MoreUtils.

Applying it to a hash of arrays is straightforward: just iterate through the keys, and apply it to each element of your hash (i.e., each array). Using your example: 

foreach (sort keys %HoA) {
    say "$_: ", join ",", uniq @{ $HoA{$_} };
}

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Output: 

flintstones: fred,barney,nick,john
jetsons: george,jane,elroy,mike,elias
simpsons: homer,marge,bart,jack

[download]

If you can't or don't want to use this module, the Perl Cookbook has several solutions (Recipe 4.6, p. 102).

In reply to Re: unique elements in a Hash of Arrays? by AppleFritter
in thread unique elements in a Hash of Arrays? by Anonymous Monk

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