We can use the flatten function when we have a collection with nested sequential collections as elements and create a new sequence with the elements from all nested collections.
In the following example we use the flatten function:
(ns mrhaki.sample (:require [clojure.test :refer [is]])) ;; Elements from nested sequential collections are flattend into new sequence. (is (= [1 2 3 4 5] (flatten [1 [2 3] [[4]] 5]))) (is (sequential? (flatten [1 [2 3] [[4]] 5]))) (is (= [1 2 3 4 5] (flatten [[1] [2 3] [[4 5]]]))) ;; We can use different sequential collection types. ;; We might have to force a type to a sequential collection with seq. (is (= '(1 2 3 4 5) (flatten [1 (seq (java.util.List/of 2 3)) ['(4 5)]]))) (is (= (quote (1 2 3 4 5)) (flatten [[1] [(range 2 6)]]))) ;; flatten on nil returns empty sequence. (is (= () (flatten nil)))
Written with Clojure 1.10.1.
