> ...repeated creation of the ephemeral vectors isn't too expensive. With Clojure, although it looks like the immutable vectors are being re-created on each iteration, under the covers it's really just pointers being updated and the operations are (about) as efficient as a loop/recur method.
> ...I don't want to traverse the collection twice. Yes, I guess that even though each filter clause is lazy they each will pass through the entire collection once. On Sun, Mar 8, 2009 at 7:53 AM, David Sletten <da...@bosatsu.net> wrote: > > > On Mar 7, 2009, at 7:17 PM, Adrian Cuthbertson wrote: > >> >> That's the beauty of this language - there are many ways to skin >> the cat! > > Hmmm...I'm not sure what I'll do with a skinless cat. :) > >> Here's a version using reduce... >> >> (defn filt-split [pred col] >> (reduce (fn [[a b] x] (if (pred x) [(conj a x) b] [a (conj b x)])) >> [[] []] col)) >> >> (filt-split even? [1 2 3 4 5 6 7 8]) >> [[2 4 6 8] [1 3 5 7]] >> > > I like that a lot. As long as the repeated creation of the ephemeral > vectors isn't too expensive. > >> But when you look at separate in clojure.contrib.seq-utils its simple >> and elegant; >> (defn separate [f s] >> [(filter f s) (filter (complement f) s)]) >> > > This is exactly what I'm trying to avoid. I don't want to traverse > the collection twice. > > Aloha, > David Sletten > > > > > --~--~---------~--~----~------------~-------~--~----~ 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 clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~----------~----~----~----~------~----~------~--~---
