indexof.cljc

indexof.cljc

;; indexOf depends on hosted language (java/javascript)

;; recurrent solution , returns -1 on not-found
(defn index-of [coll value]
  (loop [idx 0 items coll]
    (cond
      (empty? items) -1
      (= value (first items)) idx
      :else (recur (inc idx) (rest items)))))

;; high order f, lazy seq , return nil on not-found
(defn index-of [coll value]
  (some (fn [[item idx]] (if (= value item) idx))
        (partition 2 (interleave coll (iterate inc 0)))))