Clojure Koans 4 Vectors Notebook

{:hello (clojure-version)}

;; "You can use vectors in clojure as array-like structures"

(= 1 (count [42]))

;; skill 4001: Get the size/length of a Clojure vector with the `count` function

;; "You can create a vector from a list"

(= [1] (vec '(1)))

;; skill 4002: Convert a list into a vector using the `vec` function

;; "Or from some elements"

(= [nil nil] (vector nil nil))

;; skill  4003: Create a vector from some number of items using the `vector` function

;; "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"

(= [111 222 333] (conj [111 222] 333))

;; skill 4004: Append to the end of a vector by using `conj`

;; skill 4005: Prepend to (insert at) the beginning of a list by using `conj`

;; "You can get the first element of a vector like so"

(= :peanut (first [:peanut :butter :and :jelly]))

;; skill 4006: Get the 0th element of a vector using the `first` function

;; "And the last in a similar fashion"

(= :jelly (last [:peanut :butter :and :jelly]))

;; skill 4007: Get the final element of a vector using the `last` function

;; "Or any index if you wish"

(= :jelly (nth [:peanut :butter :and :jelly] 3))

;; skill 4008: Get an element of a vector at any index using the `nth` function

;; "You can also slice a vector"

(= [:butter :and] (subvec [:peanut :butter :and :jelly] 1 3))

;; skill 4009: Splice a vector using the `subvec` function

;; "Equality with collections is in terms of values"

(= (list 1 2 3) (vector 1 2 3))

;; skill 4010: Compare a vector and list with the same value contents to return true.