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You're viewing version 1.2.0 of distinct. The latest stable version of Clojure Core is 1.3.0.

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1.2.0

1.2.0
1.3.0

distinct

clojure.core

(distinct coll)

Returns a lazy sequence of the elements of coll with duplicates removed

2 Examples top

link | changes
```
user=> (distinct [1 2 1 3 1 4 1 5])
(1 2 3 4 5)
```
user=> (distinct [1 2 1 3 1 4 1 5]) (1 2 3 4 5)
link | changes
```
user=> (def fractions 
         (for [n (range 1 100) d (range (inc n) 100)] 
           (let [gcd (clojure.contrib.math/gcd n d)] 
             (/ (/ n gcd) (/ d gcd)))))
;; all irreducible fractions with denominator < 100
;; (1/2 1/3 ... 1/99 2/3 1/2 2/5 1/3 ...)

user=> (count fractions)
4851

user=> (count (distinct fractions))
3003
```
user=> (def fractions (for [n (range 1 100) d (range (inc n) 100)] (let [gcd (clojure.contrib.math/gcd n d)] (/ (/ n gcd) (/ d gcd))))) ;; all irreducible fractions with denominator < 100 ;; (1/2 1/3 ... 1/99 2/3 1/2 2/5 1/3 ...) user=> (count fractions) 4851 user=> (count (distinct fractions)) 3003

Source clojure/core.clj:3963 top

(defn distinct
  "Returns a lazy sequence of the elements of coll with duplicates removed"
  {:added "1.0"}
  [coll]
    (let [step (fn step [xs seen]
                   (lazy-seq
                    ((fn [[f :as xs] seen]
                      (when-let [s (seq xs)]
                        (if (contains? seen f) 
                          (recur (rest s) seen)
                          (cons f (step (rest s) (conj seen f))))))
                     xs seen)))]
      (step coll #{})))

Vars in clojure.core/distinct: defn let

Used in 2 other vars find-symbols find-holes

Comments top

1 comment(s) for distinct.

morphling

link

If you do not need the lazyness of distinct, set can be faster. Like: (count (set some-coll)).

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