Issue #4553 has been updated by Jonas Pfenniger. #pop is often associated to stack operations, which implies an order. Unless a better name is found, isn't set.delete(set.take) enough ? #take can be an alias of #first but I'm not sure if Enumerable should be included in Set in the first place. In my POV, Enumerable is for elements that have a particular order. ---------------------------------------- Feature #4553: Add Set#pick and Set#pop http://redmine.ruby-lang.org/issues/4553 Author: Michael Edgar Status: Open Priority: Low Assignee: Category: Target version: A very common operation on sets is to take an arbitrary element from them at O(1) cost. I know typically it's suggested that library additions go out as a gem to see community review. However, to me it seems to be a glaring omission to lack such an operation on a built-in, fundamental data structure, so I've gone straight to the bug tracker. I wasn't too sure which method names to use as I've often heard "take" in lieu of "pop," so I just used the names Wikipedia uses. Consider them flexible. "Pick" selects an arbitrary element, and "pop" selects and deletes it. I've provided a very simple patch that implements the necessary behavior. Thoughts? -- http://redmine.ruby-lang.org