clojure.core/partition-all

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Type: function Added: Clojure 1.2 Examples: 4 Runnable: 3

([n] [n coll] [n step coll])

Returns a lazy sequence of lists like partition, but may include partitions with fewer than n items at the end. Returns a stateful transducer when no collection is provided.

Examples

by nipra on 2010-07-20 ▶

(partition 4 [0 1 2 3 4 5 6 7 8 9]) ;;=> ((0 1 2 3) (4 5 6 7)) (partition-all 4 [0 1 2 3 4 5 6 7 8 9]) ;;=> ((0 1 2 3) (4 5 6 7) (8 9))

by Tap on 2012-10-07 ▶

(partition-all 2 4 [0 1 2 3 4 5 6 7 8 9]) ;;=> ((0 1) (4 5) (8 9))

by gerritjvv on 2013-07-08 . May have evaluation errors. ▶

;; Caution: Partitioning lazy sequence code freeze ;; Edit: Only because (rdr l) is buggy and returns an infinite sequence! (def l [1 2 3 4 5]) ;create a simple lazy sequence function testing only ;(rdr l) returns a lazy sequence from l (def rdr (fn reader[x] (cons (first x) (lazy-seq (reader (rest x)))))) ;the line below will freeze (doall (partition-all 2 (rdr l)) ) ;add-in a take-while statement do exit the lazy sequence on nil (doall (partition-all 2 (take-while (complement nil?) (rdr l))))

by ningDr on 2019-06-21 ▶

;; When the step parameter is provided, the starting index value of the first item in the ;; next group steps relative to the current index value ;; 提供step参数时，下一个分组的第一项的起始索引值相对于当前索引值的步进(+ pre-index step) (println (partition-all 2 3 '(0 1 2 3 4 5 6 7 8 9))) ;; => ((0 1) (3 4) (6 7) (9)) (println (partition-all 4 3 '(0 1 2 3 4 5 6 7 8 9))) ;; => ((0 1 2 3) (3 4 5 6) (6 7 8 9) (9)) ;; When n is equal to step, it is equivalent to no step parameter ;; 当n与step相等，相当于无step参数 (println (partition-all 3 3 '(0 1 2 3 4 5 6 7 8 9))) ;; => ((0 1 2) (3 4 5) (6 7 8) (9))

Note by kkprop

be aware of the case of n is 0

(partition-all 0 '(1 2 3))

will cause repl blocked and cpu 100%

See also

• clojure.core/partition (6)
• clojure.core/partition-by (3)

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