(map f)
(map f coll)
(map f c1 c2)
(map f c1 c2 c3)
(map f c1 c2 c3 & colls)
Returns a lazy sequence consisting of the result of applying f to
the set of first items of each coll, followed by applying f to the
set of second items in each coll, until any one of the colls is
exhausted. Any remaining items in other colls are ignored. Function
f should accept number-of-colls arguments. Returns a transducer when
no collection is provided.
Source
(defn map
"Returns a lazy sequence consisting of the result of applying f to
the set of first items of each coll, followed by applying f to the
set of second items in each coll, until any one of the colls is
exhausted. Any remaining items in other colls are ignored. Function
f should accept number-of-colls arguments. Returns a transducer when
no collection is provided."
{:added "1.0"
:static true}
([f]
(fn [rf]
(fn
([] (rf))
([result] (rf result))
([result input]
(rf result (f input)))
([result input & inputs]
(rf result (apply f input inputs))))))
([f coll]
(lazy-seq
(when-let [s (seq coll)]
(if (chunked-seq? s)
(let [c (chunk-first s)
size (int (count c))
b (chunk-buffer size)]
(dotimes [i size]
(chunk-append b (f (.nth c i))))
(chunk-cons (chunk b) (map f (chunk-rest s))))
(cons (f (first s)) (map f (rest s)))))))
([f c1 c2]
(lazy-seq
(let [s1 (seq c1) s2 (seq c2)]
(when (and s1 s2)
(cons (f (first s1) (first s2))
(map f (rest s1) (rest s2)))))))
([f c1 c2 c3]
(lazy-seq
(let [s1 (seq c1) s2 (seq c2) s3 (seq c3)]
(when (and s1 s2 s3)
(cons (f (first s1) (first s2) (first s3))
(map f (rest s1) (rest s2) (rest s3)))))))
([f c1 c2 c3 & colls]
(let [step (fn step [cs]
(lazy-seq
(let [ss (map seq cs)]
(when (every? identity ss)
(cons (map first ss) (step (map rest ss)))))))]
(map #(apply f %) (step (conj colls c3 c2 c1))))))