clojure-koans/04_vectors.clj

30 lines
1 KiB
Clojure

; "You can use vectors in clojure as array-like structures"
(= 1 (count [42]))
; "You can create a vector from a list"
(= [1] (vec '(1)))
; "Or from some elements"
(= [nil nil] (vector nil nil))
; "But you can populate it with any number of elements at once"
(= [1 2] (vec '(1 2)))
; "Conjoining to a vector is different than to a list"
(= __ (conj [111 222] 333))
; "You can get the first element of a vector like so"
(= :peanut (first [:peanut :butter :and :jelly]))
; "And the last in a similar fashion"
(= :jelly (last [:peanut :butter :and :jelly]))
; "Or any index if you wish"
(= :jelly (nth [:peanut :butter :and :jelly] 3)) ;; J - index #'s still start with 0 in Clojure.
; "You can also slice a vector"
(= [:butter :and] (subvec [:peanut :butter :and :jelly] 1 3)) ;; J - slicing with subvec includes first index arg and excludes second
; "Equality with collections is in terms of values"
(= true (list 1 2 3) (vector 1 2 3)) ;; J - lists and vectors are comparable.