Hi I am a clojure newbie,
I am trying to create a function that splits a collection into chunks of increasing size something along the lines of
(apply #(#(take %) (range 1 n)) col)
where n is the number of chunks
example of expected output: with n = 4 and col = (range 1 4)
(1) (2 3) (4)
with n = 7 and col = (range 1 7)
(1) (2 3) (4 5 6) (7)
You can use something like this:
(defn partition-inc
"Partition xs at increasing steps of n"
[n xs]
(lazy-seq
(when (seq xs)
(cons (take n xs)
(partition-inc (inc n) (drop n xs))))))
; (println (take 5 (partition-inc 1 (range))))
; → ((0) (1 2) (3 4 5) (6 7 8 9) (10 11 12 13 14))
Or if you want to have more influence, you could alternatively provide
a sequence for the sizes (behaves the same as above, if passed (iterate inc 1) for sizes:
(defn partition-sizes
"Partition xs into chunks given by sizes"
[sizes xs]
(lazy-seq
(when (and (seq sizes) (seq xs))
(let [n (first sizes)]
(cons (take n xs) (partition-sizes (rest sizes) (drop n xs)))))))
; (println (take 5 (partition-sizes (range 1 10 2) (range))))
; → ((0) (1 2 3) (4 5 6 7 8) (9 10 11 12 13 14 15) (16 17 18 19 20 21 22 23 24))