There's no such thing as a lazy map. into uses reduce, which is necessarily not lazy either.
Clarity is in the eye of the beholder, of course. I think my version is clearer, but if you replaced second/first with val/key I'd rate them about the same. You might even replace (just val key) with reverse - not sure if that's more readable, but there's certainly a case for it. On Sep 20, 9:52 am, John Cromartie <jcromar...@gmail.com> wrote: > On Sep 20, 12:08 pm, Alan <a...@malloys.org> wrote: > > > > > A few days ago I was thinking about how different it would be to write > > flip-map* in Java vs Clojure. A very simple, small program, but easy > > to see how Clojure can be more expressive. > > > public static Map<V,K> flipMap(Map<K,V> map) > > { > > Map<V,K> result = new HashMap<V,K>(map.size()); > > for (K key : map.keys()) { > > result.put(map.get(key), key); > > } > > > return result; > > > } > > > (def flip-map #(apply zipmap ((juxt vals keys) %))) > > > * Given a hash map, reverse its keys and values such that every K=>V > > pair in the input map becomes V=>K in the output. Naturally the values > > must be unique for this to work, so call that a precondition. > > > On Sep 17, 2:47 pm, anderson_leite <anderson...@gmail.com> wrote: > > If I was going to write flip-map it might be a tad longer, but lazy > and a bit clearer (IMO), with: > > (defn flip-map [m] (into {} (map (juxt second first) m))) -- 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