(interleave)
(interleave c1)
(interleave c1 c2)
(interleave c1 c2 & colls)
Returns a lazy seq of the first item in each coll, then the second etc.
Source
(defn interleave
"Returns a lazy seq of the first item in each coll, then the second etc."
{:added "1.0"
:static true}
([] ())
([c1] (lazy-seq c1))
([c1 c2]
(lazy-seq
(let [s1 (seq c1) s2 (seq c2)]
(when (and s1 s2)
(cons (first s1) (cons (first s2)
(interleave (rest s1) (rest s2))))))))
([c1 c2 & colls]
(lazy-seq
(let [ss (map seq (conj colls c2 c1))]
(when (every? identity ss)
(concat (map first ss) (apply interleave (map rest ss))))))))