clojure.core/when-not

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Type: macro Added: Clojure 1.0 Examples: 5 Runnable: 5

([test & body])

Evaluates test. If logical false, evaluates body in an implicit do.

Examples

by devn on 2010-08-02 ▶

;; build tuples over sets with the same cardinality (map #(when-not (= %2 %3) [%1 %2 %3]) (iterate inc 0) ; a lazy list of indecies [:a :b :c] [:a :a :a]) ;;=> (nil [1 :b :a] [2 :c :a])

by jafingerhut on 2012-04-13 ▶

;; See examples for "if" explaining Clojure's idea of logical true ;; and logical false.

by phreed on 2015-02-04 ▶

;; when-not is similar to unless (in other languages). ;; An alias can be provided with a macro (defmacro unless [& args] `(when-not ~@args)) (map #(unless (= %2 %3) [%1 %2 %3]) (iterate inc 0) ; a lazy list for indecies [:a :b :c] [:a :a :a]) ;;=> (nil [1 :b :a] [2 :c :a])

by dijonkitchen on 2019-01-07 ▶

(when-not false 2) ;; 2

by dijonkitchen on 2019-01-07 ▶

(when-not true 2) ;; nil

See also

• clojure.core/when (3)
• clojure.core/when-let (6)
• clojure.core/if (2)

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