clojure.core/range

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Type: function Added: Clojure 1.0 Examples: 5 Runnable: 4

([] [end] [start end] [start end step])

Returns a lazy seq of nums from start (inclusive) to end (exclusive), by step, where start defaults to 0, step to 1, and end to infinity. When step is equal to 0, returns an infinite sequence of start. When start is equal to end, returns empty list.

Examples

by nipra on 2010-07-15 ▶

;; default value of 'end' is infinity (range) (0 1 2 3 4 5 6 7 8 9 10 ... 12770 12771 12772 12773 ... n) ;; Since clojure 1.2: (take 10 (range)) (0 1 2 3 4 5 6 7 8 9) (range 10) (0 1 2 3 4 5 6 7 8 9) (range -5 5) (-5 -4 -3 -2 -1 0 1 2 3 4) (range -100 100 10) (-100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90) (range 0 4 2) (0 2) (range 0 5 2) (0 2 4) (range 0 6 2) (0 2 4) (range 0 7 2) (0 2 4 6) (range 100 0 -10) (100 90 80 70 60 50 40 30 20 10) (range 10 -10 -1) (10 9 8 7 6 5 4 3 2 1 0 -1 -2 -3 -4 -5 -6 -7 -8 -9)

by pkolloch on 2010-08-20 ▶

;; Since clojure 1.2: (take 10 (range)) (0 1 2 3 4 5 6 7 8 9)

by rebcabin on 2013-07-18 . May have evaluation errors. ▶

;; finite range over java Integers (take 5 (range 42 (java.lang.Integer/MAX_VALUE))) (42 43 44 45 46) ;; infinite range starting at a certain point (take 5 (drop 42 (range))) (42 43 44 45 46)

by mars0i on 2015-07-28 ▶

;; Using a double as the value of step can produce an unexpected extra value. ;; In the second example below, there's an extra final value that's almost = 0.8. (range 0 0.8 1/10) (0 1/10 1/5 3/10 2/5 1/2 3/5 7/10) (range 0 0.8 0.1) (0 0.1 0.2 0.30000000000000004 0.4 0.5 0.6 0.7 0.7999999999999999) ;; It's difficult to guess when this behavior will occur, unless you know ;; whether the double representation of step plus what "should" be the ;; last number is in fact less than end. From the second example above, you ;; can see that the extra value won't be included if you replace 0.8 by a ;; number in 0.1, ..., 0.7 (e.g. since 0.7 is not less than 0.7) but you ;; wouldn't necessarily know that you will get the extra value for end = 0.9, ;; 1.0, 1.1, but not for end = 1.2.

by st-keller on 2017-05-12 ▶

(range 0 0) () (range 0 1) (0)

See also

• clojure.core/take (3)
• clojure.core/iterate (0)

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