clojure.core/floats

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Type: function Added: Clojure 1.0 Examples: 2 Runnable: 1

([xs])

Casts to float[]

Examples

by tomdl89 on 2022-07-18 . May have evaluation errors. ▶

;; float-array will convert where possible (float-array [1 2 3]);; => [1.0, 2.0, 3.0] ;; floats will not (try (floats [1 2 3]) (catch ClassCastException e (ex-message e))) ;; => "clojure.lang.PersistentVector cannot be cast to [F"

by tomdl89 on 2023-04-23 ▶

;; Casting avoids expensive reflection, so to see the benefit, enable warning: (set! *warn-on-reflection* true) ;; We'll def a float-array but won't type-hint the var: (def my-array (float-array [10.0 20.0 30.0 40.0 50.0 60.0])) ;; and try to amap over it without using `floats` or type hinting: (amap my-array i _ (unchecked-float (unchecked-inc (aget my-array i)))) ;; Reflection warning… call to static method alength on clojure.lang.RT can't be resolved (argument types: unknown). ;; Reflection warning… call to static method aclone on clojure.lang.RT can't be resolved (argument types: unknown). ;; Reflection warning… call to static method aget on clojure.lang.RT can't be resolved (argument types: unknown, int). ;; Reflection warning… call to static method aset on clojure.lang.RT can't be resolved (argument types: unknown, int, float). ;; => [11.0, 21.0, 31.0, 41.0, 51.0, 61.0] ;; We can use `floats` to avoid reflection: (amap (floats my-array) i _ (unchecked-float (unchecked-inc (aget (floats my-array) i)))) ;; => [11.0, 21.0, 31.0, 41.0, 51.0, 61.0] ;; Just as we can type hint in place: (amap ^floats my-array i _ (unchecked-float (unchecked-inc (aget ^floats my-array i)))) ;; => [11.0, 21.0, 31.0, 41.0, 51.0, 61.0] ;; Or type hint the var: (def ^"[F" my-array (float-array [10 20 30 40 50 60])) (amap my-array i _ (unchecked-float (unchecked-inc (aget my-array i)))) ;; => [11.0, 21.0, 31.0, 41.0, 51.0, 61.0]

See also

• clojure.core/float-array (0)

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