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doc source examples comments

1.3.0

butlast

clojure.core

(butlast coll)

Return a seq of all but the last item in coll, in linear time

2 Examples top

link | changes
```
user=> (butlast [1 2 3])
(1 2)
user=> (butlast (butlast [1 2 3]))
(1)
user=> (butlast (butlast (butlast [1 2 3])))
nil
```
user=> (butlast [1 2 3]) (1 2) user=> (butlast (butlast [1 2 3])) (1) user=> (butlast (butlast (butlast [1 2 3]))) nil
link | changes
```
;really slow reverse
;put the last item of the list at the start of a new list, and recur over all but the last item of the list.
;butlast acts similar to next in that it returns null for a 1-item list.

(defn my-reverse
  ([a-list]
     (cond (= a-list nil) nil
           :else (cons (last a-list)
                       (my-reverse (butlast a-list))))))
```
;really slow reverse ;put the last item of the list at the start of a new list, and recur over all but the last item of the list. ;butlast acts similar to next in that it returns null for a 1-item list. (defn my-reverse ([a-list] (cond (= a-list nil) nil :else (cons (last a-list) (my-reverse (butlast a-list))))))

Source clojure/core.clj:252 top

(def 
 ^{:arglists '([coll])
   :doc "Return a seq of all but the last item in coll, in linear time"
   :added "1.0"
   :static true}
 butlast (fn ^:static butlast [s]
           (loop [ret [] s s]
             (if (next s)
               (recur (conj ret (first s)) (next s))
               (seq ret)))))

Vars in clojure.core/butlast:

Used in 0 other vars

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Clojure Core

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butlast

clojure.core

2 Examples top

See Also top

Source clojure/core.clj:252 top

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