I am reading data out of a flatfile including names, employee classifications, and countries to get statistics. Since I'm only concerned about numbers, I've made hashes for each classification %class1{'countryname'}, etc.

Now to get the number of countries represented within class1, I use scalar(keys(%class1)).

My question is how to get the number of countries represented in the whole company.

Here is my (correctly working) code: 

foreach (keys(%class1),keys(%class2),keys(%class3)) {
  $tot{$_}=1;
}
$t=scalar(keys(%tot));

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Is this the "right" way to do this? Is there another way? Also, is it possible to "merge" two hashes in an automatic way? (My hunch is "no" because Perl can't know what to do with overlapping keys, but I thought I'd ask...)

In reply to Combining hashes by mpolo

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