You may be interested in the core function 'interleave'. As for (into []), it's perfectly idiomatic as long as you actually need to return a vector and not just some kind of sequence (the more common case). But note also the mapv/filterv/reduce-kv family of functions, though they're not directly applicable here.
On Feb 18, 2014, at 22:58 , Laurent Droin <laurentdr...@gmail.com> wrote: > Hi, > > Continuing my little pet project (small program really) to learn Clojure, I > am now working on a function whose description would be something like: > "Returns a collection 'weaving' 2 collections (boundaries into categories). > Boundaries must have one element less than categories. > For example, if categories is [:z1 :z2 :z3 :z4 :z5] > and boundaries is [120 150 165 180] > returns [:z1 120 :z2 150 :z3 165 :z4 180 :z5]" > > Assume the precondition is enforced. > If categories has n elements, boundaries has n-1. > > I have tried to come up with a good implementation. I actually came up with > two, one that is non recursive, and one that is recursive. But I'm not fully > satisfied. I have the feeling that it's possible to make the function > simpler, and more elegant but I only know a subset of Clojure and am surely > missing some good idioms that I could/should be using. > So once again, relying on feedback from experienced Clojurists to show me the > way :-) > > Here is what I have so far: > > 1- the non recursive function - based on mapcat > (defn build-quantize-defs > > > [categories boundaries] > > > (conj (into [] (mapcat #(vector %1 %2) categories boundaries)) (last > categories))) > > 2 - the recursive function > (defn build-quantize-defs-recur [categories boundaries] > > > (let [c (first categories) b (first boundaries)] > > > (if (nil? b) > > > [c] > > > (into [] (concat [c] [b] (build-quantize-defs-recur (rest categories) (rest > boundaries))))))) > > Both functions work (on my example at least). > > One of the things I don't like, is my abusing (or the feeling that I am > abusing anyway) of this "into [] " idiom. I find myself constantly turning > things into vectors. That doesn't seem right and maybe I am using it in > places it's not needed. That's probably because I don't quite have a very > good idea of how collections work just yet. > > Thanks for any feedback. -- 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 unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
