clojure.core/rest

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Type: function Added: Clojure 1.0 Examples: 6 Runnable: 6

([coll])

Returns a possibly empty seq of the items after the first. Calls seq on its argument.

Examples

by MrHus on 2010-07-18 ▶

(rest [1 2 3 4 5]) ;;=> (2 3 4 5) (rest ["a" "b" "c" "d" "e"]) ;;=> ("b" "c" "d" "e")

by hoornet on 2011-04-06 ▶

;; For the most part rest must take a collection as its argument. ;; It always returns a seq. (rest '()) ;;=> ()

by steveminer on 2011-06-02 ▶

;; There is one case where the input is not required to be a collection. ;; But, 'rest' still returns a list. (rest nil) ;;=> ()

by steveminer on 2011-06-02 ▶

;; A simple (re-)implementation of 'map' using 'rest' for recursing over a collection. ;; Note that (seq coll) is used as the test. (defn my-map [func coll] (when-let [s (seq coll)] (cons (func (first s)) (my-map func (rest s))))) (my-map #(* % %) [2 3 5 7 11 13]) ;;=> (4 9 25 49 121 169)

by TravisHeeter on 2013-11-23 ▶

;; Any collection can be used (rest '(1 2 3 4 5)) ;;=> (2 3 4 5) (rest [1 2 3 4 5]) ;;=> (2 3 4 5) (rest #{1 2 3 4 5}) ;;=> (2 3 4 5) (rest {1 nil 2 nil 3 nil 4 nil 5 nil}) ;;=> ([2 nil] [3 nil] [4 nil] [5 nil])

by Dimagog on 2015-02-04 ▶

;; Difference between next and rest: (rest [:a]) ;; => () (next [:a]) ;; => nil (rest []) ;; => () (next []) ;; => nil (rest nil) ;; => () (next nil) ;; => nil

Note by steveminer

rest is generally preferred over next. See the Clojure.org documentation on writing lazy functions.

Also, the topic is covered on StackOverflow.com: rest vs. next.

See also

• clojure.core/next (2)
• clojure.core/first (2)
• clojure.core/drop (2)
• clojure.core/pop (2)
• clojure.core/nthrest (4)
• clojure.core/nthnext (2)

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