clojure.core/bounded-count

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Type: function Added: Clojure 1.9 Examples: 2 Runnable: 1

([n coll])

If coll is counted? returns its count, else will count at most the first n elements of coll using its seq

Examples

by svenschoenung on 2017-05-24 ▶

;;;; Length of a vector can be determined in constant time ;;;; so this always returns the actual length of the vector (bounded-count 5 [1 2 3 4]) ;;=> 4 (bounded-count 5 [1 2 3 4 5]) ;;=> 5 (bounded-count 5 [1 2 3 4 5 6]) ;;=> 6 ;;;; Length of a lazy seq cannot be determined in constant time ;;;; so this counts at most the first 5 elements (bounded-count 5 (map identity [1 2 3 4])) ;;=> 4 (bounded-count 5 (map identity [1 2 3 4 5])) ;;=> 5 (bounded-count 5 (map identity [1 2 3 4 5 6])) ;;=> 5

by svenschoenung on 2017-05-24 . May have evaluation errors. ▶

;;;; This would run forever (count (range)) ;;;; But this doesn't (bounded-count 10000 (range)) ;;=> 10000

See also

• clojure.core/counted? (1)

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