https://gist.github.com/alexpw/f20c7b3ac858003e07e2
This version supports the missing case: ;; Case: false match :b, followed by true match :b :c (= (partition-by-seq [:b :c] [:a :b :b :c :e :d :a :b :c :d :a :b :c]) '((:a :b) (:b :c) (:e :d :a) (:b :c) (:d :a) (:b :c))) On Sunday, June 8, 2014 8:52:09 AM UTC-5, Alex Walker wrote: > > Err, this was bugging me all day when I went afk. I wrote it too quickly > and am missing the case where the sub-seq starts right after seeing the > first val, [:b :b :c]. > > Will fix it if I have time today, but may need to take a slightly > different approach. Fun problem, btw. :) > > On Saturday, June 7, 2014 2:31:04 PM UTC-5, Alex Walker wrote: >> >> Here's a solution based on your description that behaves like core >> partition fns, taking liberty to presume your example should've matched the >> output below. >> >> (defn partition-by-seq >> [sub-seq coll] >> (letfn [(step [coll] >> (when-let [coll (seq coll)] >> (let [[run more] (split-with (partial not= (first sub-seq)) >> coll) >> [possible-match more] (split-at (count sub-seq) more)] >> (if (= possible-match sub-seq) >> (if (seq run) >> (cons run (cons possible-match (lazy-seq (step >> more)))) >> (cons possible-match (lazy-seq (step >> more)))) >> (cons (concat run possible-match) (lazy-seq (step >> more)))))))] >> (or (step coll) ()))) >> >> => (partition-by-seq [:b :c] []) >> >> () >> >> => (partition-by-seq [:b :c] [:a :d]) >> >> ((:a :d)) >> >> => (partition-by-seq [:b :c] [:a :b :c :d :a :b :c :d :a :b :c]) >> >> ((:a) (:b :c) (:d :a) (:b :c) (:d :a) (:b :c)) >> >> >> >> On Tuesday, June 3, 2014 4:05:16 AM UTC-5, Ulrich Küttler wrote: >>> >>> Hi, >>> >>> what is the preferred way to find sub-seqs in a seq? I am trying to >>> convert >>> >>> [:a :b :c :d :a :b :c :d :a :b :c] >>> >>> into >>> >>> ((:a) (:b :c) (:a :d) (:b :c) (:a)) >>> >>> using the sub-seq (:b :c) instead of positions. >>> >>> partition, partition-by and the like all look at one element at a time. >>> What I need is a search based on seqs. Are there functions that support >>> such a search / split? >>> >>> Uli >>> >> -- 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/d/optout.
