Andrei, You could just bind another local variable in the loop form: (loop [ps pairs ret {} ffps (ffirst ps)] (cond (empty? ps) ret (some-test ffps) (recur (rest ps) (add-to-result ret ffps) (ffirst (rest ps))) :true (recur (rest ps) (do-sth-else ret ffps) (ffirst (rest ps)))) )
I think I like Andrew's solution better though. But you probably want to use 'reduce' instead of 'loop' anyway: (reduce (fn [ret [key val]] (if (some-test key) (add-to-result ret key) (do-sth-else ret key))) {} pairs) Notice how you can destructure each pair in a convenient way. BTW, do you really mean to call 'add-to-result' and 'do-sth-else' with a map and a key but no value? Have all good days, David Sletten On Oct 28, 2010, at 8:49 PM, andrei wrote: > Hi, > > I have a code similar to this: > > (def pairs (list [1 :a] [2 :b] [3 :c])) > ... > (loop [ps pairs, ret {}] > (cond (empty? ps) ret > (some-test (first (first ps))) (recur (rest ps) (add-to- > result ret (first (first ps)))) > :true (recur (rest ps) (do-smth-else ret (first (first > ps)))))) > > You can see that string (first (first ps)), which actually gets first > element of a first vector in pairs, occur many times. I can't move it > before cond, since ps may be empty and evaluating of (first (first > ps)) will produce an error (ok, it won't, but in general case it may). > Is there another way to simplify code to not repeat one form several > times? > > -- > 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 -- 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