clojure.core/vector?

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Type: function Added: Clojure 1.0 Examples: 3 Runnable: 2

([x])

Return true if x implements IPersistentVector

Examples

by dpritchett on 2010-07-14 ▶

;; this is the idiomatic vector (vector? [1 2 3]) ;;=> true ;; a list is not a vector (vector? '(1 2 3)) ;;=> false ;; a list may be converted into a vector (vector? (vec '(1 2 3))) ;;=> true ;; a map is not a vector (vector? {:a 1 :b 2 :c 3}) ;;=> false ;; a set is not a vector (vector? #{:a :b :c}) ;;=> false (first {:a 1 :b 2 :c 3}) ;;=> [:c 3] (vector? (first {:a 1 :b 2 :c 3})) ;;=> true

by humorless on 2018-02-18 ▶

;; an quoted vector is still a vector (vector? '[]) ;;=> true

by KGOH on 2022-08-19 . May have evaluation errors. ▶

;; Be careful while traversing data: ;; map entries are vectors! (vector? (first {:a 1})) true (vector? (clojure.lang.MapEntry. :a 1)) true (clojure.walk/postwalk #(cond-> % (vector? %) set) {:a [1 1 2 3]}) ; Unhandled java.lang.ClassCastException ; class clojure.lang.PersistentHashSet cannot be cast to class ; java.util.Map$Entry (clojure.lang.PersistentHashSet is in unnamed module of ; loader 'app'; java.util.Map$Entry is in module java.base of loader ; 'bootstrap') (clojure.walk/postwalk #(cond-> % (and (vector? %) (not (map-entry? %))) set) {:a [1 1 2 3]}) {:a #{1 3 2}}

See also

• clojure.core/set?
• clojure.core/vec (1)
• clojure.core/map? (1)
• clojure.core/list? (2)
• clojure.core/sequential? (1)

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