clojure.core/inc

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Type: function Added: Clojure 1.2 Examples: 4 Runnable: 2

([x])

Returns a number one greater than num. Does not auto-promote longs, will throw on overflow. See also: inc'

Examples

by zk on 2010-07-24 ▶

(inc 1) 2 (inc 1.0) 2.0 (inc 1/2) 3/2 (inc -1) 0

by ibercode on 2018-01-17 ▶

;;increment all the element in a collection (map inc [1 2 3 4 5]) ;;(2 3 4 5 6) return type list (into [] (map inc [1 2 3 4 5])) ;;[2 3 4 5 6] return type vector

by wuleicanada on 2018-04-25 . May have evaluation errors. ▶

;; Careful when using ClojureScript ;; Make sure you're passing a number ;; because JavaScript + also does string concatenation (inc "1") "11" (inc 1) 2 ;; Although it's not the case with dec ;; In JavaScript "1" - 1 = 0 (dec "1") 0 (dec 1) 0

by Crowbrammer on 2021-10-01 . May have evaluation errors. ▶

;; You cannot `inc` a `nil` in Clojure, but you ;; can in ClojureScript ;; Clojure (inc nil) ;;=> NullPointerException ;; ClojureScript (inc nil) ;;=> 1

Note by icefox

Is the documentation suppose to be: "Returns a number one greater than x." ? If not what is num?

Note by arashgithub

is code "(def i (inc i))" is conflict with the notion of immutable of data in Clojure.

Note by reborg

Nope, quite the opposite. "def" defines a var:

user=> (type (def i 1))
clojure.lang.Var

A var is one of the 4 types dealing with mutable state (it is not an immutable data structure, like maps, vectors, sets and so on) and it does so following a specific semantic (see http://clojure.org/reference/vars).

See also

• clojure.core/dec
• clojure.core/inc' (0)
• clojure.core/unchecked-inc (1)

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