On Oct 3, 9:32 am, Alan <a...@malloys.org> wrote: > I've got a collection of unique objects, and I need to partition them > into sets. That part's easy enough, but I need to have both of the > following be efficient, and preferably easy: > - Given an object, determine what set it's in > - List all the objects in a given set > I'm sure you'll get better answers later but this is the pseudo code for what I would do.
1. Separate your objects into clojure sets. This makes it quick and easy to list the objects in a given set. 2. To find out which set an object is in, do a get on each set until a non nil return value is seen using (some #(% obj) [my-sets]) > > I could construct all the objects and have a single "global" map, with > mappings for both set-id=>[objects] and object=>set-id, but this seems > kinda gross and obscures what is actually meant (objects belong to > sets) with implementation (integers/keywords mapping to groups of > objects, and objects mapping to integers). > 3. Only the mapping, object => set, is needed and, as you say, this is an implementation detail that should be hidden. So memoize step 2 for performance. You get a global map but it doesn't clutter your code. Saul -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
