http://www.perlmonks.org?node_id=504599


in reply to Count and List Items in a List

When you think "unique" and "frequency", think of a hash. Its keys are always unique, and you can use its values as a place to store the number of times each key shows up:
for my $word (@list) { $frequency{$word}++; }
Now the %frequency hash holds each word (but only once!) and $frequency{$some_word} is the number of times $some_word appeared in @list.

Jeff japhy Pinyan, P.L., P.M., P.O.D, X.S.: Perl, regex, and perl hacker
How can we ever be the sold short or the cheated, we who for every service have long ago been overpaid? ~~ Meister Eckhart