clojure.core/persistent!

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Type: function Added: Clojure 1.1 Examples: 2 Runnable: 1

([coll])

Returns a new, persistent version of the transient collection, in constant time. The transient collection cannot be used after this call, any such use will throw an exception.

Examples

by yasuto on 2011-06-10 . May have evaluation errors. ▶

(def foo (transient [1 2 3])) #'user/foo foo #<TransientVector clojure.lang.PersistentVector$TransientVector@12c9b4d1> (persistent! foo) [1 2 3] foo #<TransientVector clojure.lang.PersistentVector$TransientVector@12c9b4d1> (conj! foo 4) → ERROR:Transient used after persistent! call (persistent! foo) → ERROR: Transient used after persistent! call

by mattvvhat on 2015-04-09 ▶

;; Use persistent! to evaluate your object, ;; once the computation is complete (loop [large-set (transient #{}) i 0] (if (< i 100000) (recur (conj! large-set i) (inc i)) (persistent! large-set))) ;; Returns a large set *much* faster than its ;; persistent version. While keeping the same ;; code structure

See also

• clojure.core/transient (2)

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