I had assumed when he wrote "do not use iteration", what he meant is to "not use for/next loop"
otherwise, as you said, we can't solve the problem without examining the sequence. On Fri, Jan 29, 2010 at 2:38 PM, Meikel Brandmeyer <m...@kotka.de> wrote: > Hi, > > Am 29.01.2010 um 16:25 schrieb Wilson MacGyver: > >> I saw this on twitter. >> >> http://pastie.org/796264 >> >> The problem: given a list of strings, produce a list where sequential >> non-empty strings are concatenated >> >> # Conditions: Do not use iteration. >> # >> # Example: glom (["a", "b", "c"]) = ["abc"] >> # glom (["a", "", "b"]) = ["a", "b"] >> # glom (["a", "b", "", "c"]) = ["ab", "c"] >> # glom (["a", "b", "", "", "c"]) = ["ab", "c"] >> >> >> The author had rules like, don't use iteration and avoid recursion. >> >> anyone have any clever solutions? My first reaction was to use reduce, but >> I'm not sure how that'd work. > > I don't know the definition of iteration, but for my (naive, hobbyist) > understanding you won't get around it. Recursion is just another form. A map > call is just another form. A reduce call is just another form. You have to > walk the sequence in one way or the other and I would call that „iteration“. > But I called the shot already in the sieve thread. So I will shut up now. > Please enlighten me if this is totally wrong. > > Here a recursive definition. > > (defn glom > [coll] > (lazy-seq > (when-let [s (seq coll)] > (let [[items tail] (split-with (complement empty?) s) > tail (drop-while empty? tail)] > (cons (apply str items) (glom tail)))))) > > Sincerely > Meikel > > -- > 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 -- Omnem crede diem tibi diluxisse supremum. -- 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
