clojure.core/sequential?

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Type: function Added: Clojure 1.0 Examples: 2 Runnable: 1

([coll])

Returns true if coll implements Sequential

Examples

by rustem.suniev on 2010-09-19 ▶

;; You may also find this useful: https://insideclojure.org/2015/01/02/sequences (sequential? '(1 2 3)) true (sequential? [1 2 3]) true (sequential? (range 1 5)) true (sequential? '()) true (sequential? []) true (sequential? nil) false (sequential? 1) false (sequential? "abc") false (sequential? {:a 2 :b 1}) false (sequential? #{1 2 3}) false

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

;; Be careful while traversing data: ;; map entries are vectors and thus sequential! (sequential? (first {:a 1})) true (sequential? (clojure.lang.MapEntry. :a 1)) true (vector? (first {:a 1})) true (vector? (clojure.lang.MapEntry. :a 1)) true (clojure.walk/postwalk #(cond-> % (sequential? %) 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 (sequential? %) (not (map-entry? %))) set) {:a [1 1 2 3]}) {:a #{1 3 2}}

Note by zackteo

Of the four key collection types, vectors and lists are ordered (aka sequential). Sets and maps are not.

See also

• clojure.core/seq? (2)
• clojure.core/coll? (4)
• clojure.core/seqable? (0)

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