Well, if there is an exact match, it's no roulette. There are quite simple techniques to verify a hash key actually exists. In fact, like janx noted above, there's Tie::Hash::Approx by our very own OeufMayo which does pretty much just that :)

Tie::Hash::Approx - Approximative match of hash keys using String::Approx

Greetz
Beatnik
... Quidquid perl dictum sit, altum viditur.