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      take-nth

      clojure.core

      自 1.0 起可用 (源)
      • (take-nth n)
      • (take-nth n coll)
      Returns a lazy seq of every nth item in coll.  Returns a stateful
transducer when no collection is provided.
      © Rich Hickey。保留所有权利。 Eclipse 公共许可证 1.0
      2 Examples
      user=> (take-nth 2 (range 10))
(0 2 4 6 8)

      ;; N <= 0 is a special case
(take 3 (take-nth 0 (range 2)))
;;=> (0 0 0)

(take 3 (take-nth -10 (range 2)))
;;=> (0 0 0)
      See Also
      clojure.core/partition

      Returns a lazy sequence of lists of n items each, at offsets step apart. If step is not supplied, ...

      Added by kappa
      clojure.core/nth

      Returns the value at the index. get returns nil if index out of bounds, nth throws an exception un...

      Added by MicahElliott
      clojure.core/rand-nth

      Return a random element of the (sequential) collection. Will have the same performance characteris...

      Added by MicahElliott
      3 Notes
        By , created 10.2 years ago

        (take-nth 0 (range 10)) will loop forever.

        By , created 9.9 years ago

        (take-nth 0 coll) will return an infinite sequence repeating for first item from coll. A negative N is treated the same as 0.

        By , created 7.1 years ago, updated 7.1 years ago
        ;; In case you are searching for it, drop-nth is not in core.

(defn drop-nth [n coll]
  (lazy-seq
    (when-let [s (seq coll)]
      (concat (take (dec n) (rest s))
              (drop-nth n (drop n s))))))

(drop-nth 3 (range 10))
;; (1 2 4 5 7 8)

;; or alternatively: (keep-indexed #(when-not (zero? (rem %1 n)) %2) coll)