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pervognsen/indexed-pred.clj

Created March 20, 2010 13:54
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indexed-pred.clj
;; general utility. like reduce but gives a list of all intermediate results.
(defn scan [f val coll]
(if-let [s (seq coll)]
(lazy-seq (cons val (scan f (f val (first s)) (rest s))))
[val]))
(defn indexed-pred [pred coll]
(map #(if (pred %1) [%2 %1] [%1]) coll (scan + 0 (map #(if (pred %) 1 0) coll))))
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