ClojureDocs

Nav

Namespaces

ClojureDocs
    ClojureDocs
      Namespaces

      reverse

      clojure.core

      Available since 1.0 (source)
      • (reverse coll)
      Returns a seq of the items in coll in reverse order. Not lazy.
      © Rich Hickey. All rights reserved. Eclipse Public License 1.0
      3 Examples
      user=> (reverse '(1 2 3))
(3 2 1)

      (reverse "clojure")
; (\e \r \u \j \o \l \c)

(apply str (reverse "clojure"))
; "erujolc"
      ;; Comparison between `reverse` and `rseq` for a vector.

(def nums (vec (range 1000000)))
(time (reverse nums))
;; "Elapsed time: 30.1222 msecs"
(time (rseq nums))
;; "Elapsed time: 0.0664 msecs"
      See Also
      clojure.core/rseq

      Returns, in constant time, a seq of the items in rev (which can be a vector or sorted-map), in rev...

      Added by gstamp
      2 Notes
        By , created 14.3 years ago

        If you've got a vector rseq is a good option instead of reverse.

        By , created 4.1 years ago, updated 4.1 years ago

        For vectors, rseq is to reverse what peek is to last. rseq reverses in constant time (!) where reverse is in linear time, as it appears to pull everything into a new seq, one at a time instead of ... reversing the keys? I don't know the implementation details, but I do know that rseq is magnitudes faster than reverse for vectors and sorted maps.