Clojure, concat multiple sequences into one

Question

The following line: (repeat 4 [2 3])

gives me this: ([2 3] [2 3] [2 3] [2 3])

How do I create one vector or list from the above list of vectors so that I get this?: [2 3 2 3 2 3 2 3]

Thanks

Answer 1

concat is in fact exactly the function you want

user> (apply concat (repeat 4 [2 3]))
(2 3 2 3 2 3 2 3)

this even works with lazy input:

user> (take 8 (apply concat (repeat [2 3])))
(2 3 2 3 2 3 2 3)

This is an alternative:

user> (def flatten-1 (partial mapcat identity))
#'user/flatten-1
user> (flatten-1 (repeat 4 [2 3]))
(2 3 2 3 2 3 2 3)

it is compatible with laziness and unlike flatten preserves any substructure (only doing one level of flattening)

user> (take 12 (flatten-1 (repeat [2 3 [4]])))
(2 3 [4] 2 3 [4] 2 3 [4] 2 3 [4])

Answer 2

(take 8 (cycle [2 3]))
;; => (2 3 2 3 2 3 2 3)