Could do it this way. Use index-filter (borrowed from Programming Clojure) to get the indices where the predicate is true in the sequence. partition-when-true then just calls subvec with pairs of indices to get the subsequences.
coll-end is the index just past the end of the collection. This is used as a pad element so that the last true index is included in the pairs, and also accounts for the case where there is only a single true index. (use '[clojure.contrib.seq :only (indexed)]) (defn index-filter [pred coll] (when pred (for [[idx elt] (indexed coll) :when (pred elt)] idx))) (defn partition-when [pred coll] (let [coll-end (count coll) indices (index-filter pred coll) index-pairs (partition 2 1 [coll-end] indices) coll-vec (vec coll)] (for [[start end] index-pairs] (subvec coll-vec start end)))) user=> (partition-when true? '(true false false true false true true)) ([true false false] [true false] [true] [true]) On Nov 27, 10:02 am, Asim Jalis <asimja...@gmail.com> wrote: > I want to partition a sequence based on the values of a predicate so > that every true starts a new sequence in the partition. Here is an > example of how partition-with could be used: > > (partition-when true? '(true false false true false true true)) > -> '((true false false) (true false) (true) (true)) > > I have written this lazy-seq and recursion. However, I was wondering > if there is a way to do this with core Clojure sequence primitives. > Any suggestions? > > Asim > -- > San Francisco, CA -- 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