On Aug 16, 12:02 pm, botgerry <botge...@gmail.com> wrote: > Hello,all > > I'm new to functional programming,want to know how to address nested > inner seqs in clojure > > (def a [[1 2 3 4] [ "ok" "metoo"] [ 5 8 9 ]]) > > 1: searching in a, if find one inner vector includes number 9 then > append it a number 13 > [[1 2 3 4] [ "ok" "metoo"] [ 5 8 9 ]] => [[1 2 3 4] [ "ok" "metoo"] > [ 5 8 9 13]] > > 2: searching in a, if found two or many inner vectors include same > element the merge them as one inner vector > others not touch > > (def b ( conj a [ 5 10 "oops"])) => [[1 2 3 4] ["ok" "metoo"] [5 8 > 9] [5 10 "oops"]] > in b, [5 8 9] and [5 10 "oops"] both include 5, it should be merge to > [5 8 9 10 "oops"] : > [[1 2 3 4] ["ok" "metoo"] [5 8 9] [5 10 "oops"]] => [[1 2 3 4] ["ok" > "metoo"] [5 8 9 10 "oops"]] > > I only found one solution to question 1 using zipper : > (def dz (zip/vector-zip a)) > (defn append-to-blocks [x y] ;lookup x in blocks,if found then add y > to inner block > (loop [loc dz] ;dz is blocks > (if (zip/end? loc) > (zip/root loc) > (recur > (zip/next > (if (and (vector? (zip/node loc)) (includes? (zip/node loc) x)) > (let [new-coll (conj (zip/node loc) y)] > (zip/replace loc new-coll)) > loc)))))) > > user=> (append-to-blocks 9 13) > [[1 2 3 4] ["ok" "metoo"] [5 8 9 13]]
I think using a zipper is a good solution > but still not figure out one way to question 2, i have tried: > (defn merge-inner-blocks [x blocks] ;x is element maybe in many inner > blocks > (let [with-out-x (for [b blocks :when (not (includes? b x))] b) > with-x (for [b blocks :when (includes? b x)] b)] > (def blocks (concat with-out-x (vector (flatten with-x)))))) ; > just merge them, not remove the same element You should never use def inside a function. It's a certain sign that you're doing something wrong. Why don't you just return the result normally? That said, I can't think of a fast solution for this either; but you can wrap the (concat ...) in (vec (set ...)) to get a vector of uniques. > (merge-inner-blocks 5 b) > #'user/blocks > user=> blocks > ([1 2 3 4] ["ok" "metoo"] (5 8 9 5 10 "oops")) ; here how to remove > one of the "5"? vector has changed to list? > > 3, I also found my solutions to this alike problems are not > concise,and a bit ugly, any libs or appropriate way to process inner > nested seqs in clojure? i thought those ops maybe frequently > encountered in practical programming I have to say I haven't had the need to do much with nested seqs, but I suppose for that purpose clojure.zip would be worth learning more in depth. It is designed for traversing and "editing" data structures, after all. -- Jarkko --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
