mapn.clj

mapn.clj

(defn mapn
  ([n f coll]
     (->> (partition n coll)
          (map (partial apply f))))
  ([n m f coll]
     (->> (partition n m coll)
          (map (partial apply f))))
  ([n m k f coll]
     (->> (partition n m k coll)
          (map (partial apply f)))))

(def mapncat
  #(mapcat identity (apply mapn %&)))

;; examples
(def zeros (repeat 0))

(mapn 3 list [1 2 3 4 5 6 7 8])     ;=> ((1 2 3) (4 5 6))
(mapn 3 1 list [1 2 3 4 5 6 7 8])   ;=> ((1 2 3) (2 3 4) (3 4 5) (4 5 6) (5 6 7) (6 7 8))
(mapn 3 2 zeros list [1 2 3 4 5 6 7 8]) ;=> ((1 2 3) (3 4 5) (5 6 7) (7 8 0))

(mapn 3 + [1 2 3 4 5 6 7 8])          ;=> (6 15)
(mapn 3 1 + [1 2 3 4 5 6 7 8])        ;=> (6 9 12 15 18 21)
(mapn 3 2 zeros + [1 2 3 4 5 6 7 8])  ;=> (6 12 18 15)

(mapncat 2 1 zeros list [1 2 3 4 5 6 7 8]) ;=> (1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 0)