Sliding window over seq

Question

In Clojure, what would be the nicest way to have a sliding window over a (finite, not too large) seq? Should I just use drop and take and keep track of the current index or is there a nicer way I'm missing?

score 32 · Accepted Answer · answered Sep 15 '09 at 17:05

32

I think that partition with step 1 does it:

user=> (partition 3 1 [3 1 4 1 5 9])
((3 1 4) (1 4 1) (4 1 5) (1 5 9))

answered Sep 15 '09 at 17:05

Jonas

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score 3 · Answer 2 · answered Sep 16 '09 at 00:52

3

If you want to operate on the windows, it can also be convenient to do this with map:

user=> (def a [3 1 4 1 5 9])
user=> (map (partial apply +) (partition 3 1 a))
(8 6 10 15)
user=> (map + a (next a) (nnext a))
(8 6 10 15)

answered Sep 16 '09 at 00:52

Timothy Pratley

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score 1 · Answer 3 · answered Jun 18 '19 at 08:49

I didn't know partition could do this so I implemented it this way

(defn sliding-window [seq length]
  (loop [result ()
         remaining seq]
    (let [chunk (take length remaining)]
      (if (< (count chunk) length)
        (reverse result)
        (recur (cons chunk result) (rest remaining))))))

Sliding window over seq

3 Answers3