SunRaySon wrote: > Are there any general guidelines on when a "Set" should be used and when a > "Hash" should be used. Are there any limitations to "Set" A Set is similar to an Array - the two major differences are that a Set is unordered (because it's implementation is based on a Hash) and that a Set contains every element only once (i.e. if you add an element which is already there, the Set won't change). You should use a Hash if you have a dictionary-like structure (i.e. key => value pairs) and a Set/Array if you have single objects. You can think about a Set as a Hash where every value is nil - i.e. you can represent a Set with a Hash but it makes no sense if you are not using any values at all. In this case you should use a Set. I hope this answers your question... Cheers, Peter __ http://www.rubyrailways.com :: Ruby and Web2.0 blog http://scrubyt.org :: Ruby web scraping framework http://rubykitchensink.ca/ :: The indexed archive of all things Ruby