List.find<'T> Function (F#)

Returns the first element for which the given function returns true. Raises KeyNotFoundException if no such element exists.

Namespace/Module Path: Microsoft.FSharp.Collections.List

Assembly: FSharp.Core (in FSharp.Core.dll)

// Signature:
List.find : ('T -> bool) -> 'T list -> 'T

// Usage:
List.find predicate list

Parameters

• predicate
  Type: 'T ->bool

  The function to test the input elements.

• list
  Type: 'Tlist

  The input list.

Exceptions

Exception	Condition
KeyNotFoundException	Thrown if the predicate evaluates to false for all the elements of the list.

Return Value

The first element that satisfies the predicate.

Remarks

This function is named Find in compiled assemblies. If you are accessing the function from a language other than F#, or through reflection, use this name.

Example

The following code example illustrates the use of List.find.

let isDivisibleBy number elem = elem % number = 0
let result = List.find (isDivisibleBy 5) [ 1 .. 100 ]
printfn "%d " result

Output

5

Platforms

Windows 8, Windows 7, Windows Server 2012, Windows Server 2008 R2

Version Information

F# Core Library Versions

Supported in: 2.0, 4.0, Portable

See Also

Reference

Collections.List Module (F#)

Microsoft.FSharp.Collections Namespace (F#)