One way I could think of to do this would be to build a map with each unique item as a key and the count as its value. Then it would be trivial to pull out the keys with the count as a specified value. I started writing this, but my SLIME is royally screwed up right now after the upgrade to Clojure HEAD. Sorry. Anyway, it shouldn't require any refs - probably just a loop/recur.
Or maybe someone has a far more clever idea. :) > On Sun, Nov 16, 2008 at 12:02 PM, npt11tpn <[EMAIL PROTECTED]> wrote: > > > Hi guys, > This is my first post to the group, but have been following the > discussions for almost a year. Many thanks to Rich Hickey for creating > a fantastic future-proof language which is a pleasure to use and to > the great community! > The following function (as part of a chemistry-related application) > filters the elements of a sequence that a repeated a specified number > of times. Wondering if the function could be simplified and written > without the reference (newseq). > Thanks a lot! > Nik > > (defn filter-repeats [seq n] > "Returns a vector of the elements of a sequence that are repeated n > times" > (let [newseq (ref [])] > (doseq [u (set seq)] > (when (= (count (filter #(= % u) seq)) n) > (dosync (commute newseq conj u)))) > @newseq)) > > Usage e.g. > (filter-repeats '(2 3 1 4 2 2 4 3 5 ) 2) > [3 4] > > > > > --~--~---------~--~----~------------~-------~--~----~ 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 To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~----------~----~----~----~------~----~------~--~---
