Array.find<'T> Function (F#)
Returns the first element for which the given function returns true. Raise KeyNotFoundException if no such element exists.
Namespace/Module Path: Microsoft.FSharp.Collections.Array
Assembly: FSharp.Core (in FSharp.Core.dll)
Thrown if predicate does not return true for any element.
The following example demonstrates the use of Array.find and Array.findIndex to identify the first integer greater than 1 that is both a square and a cube.
let arrayA = [| 2 .. 100 |] let delta = 1.0e-10 let isPerfectSquare (x:int) = let y = sqrt (float x) abs(y - round y) < delta let isPerfectCube (x:int) = let y = System.Math.Pow(float x, 1.0/3.0) abs(y - round y) < delta let element = Array.find (fun elem -> isPerfectSquare elem && isPerfectCube elem) arrayA let index = Array.findIndex (fun elem -> isPerfectSquare elem && isPerfectCube elem) arrayA printfn "The first element that is both a square and a cube is %d and its index is %d." element index
The first element that is both a square and a cube is 64 and its index is 62.