In any normal hash, no two keys can be the same anyway. Assuming that you mean that you need to check that a key doesn't already exist, you can use exists, like this:

my %hash;
my $key = "test";

if (exists $hash{$key}) {
   # do something
} else {
   # do something else
}
[download]

You're question's not particularly clear, and that's a complete stab in the dark *grin* - could you post a little more about what it is you're trying to achieve?

-- Foxcub
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