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

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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: 'T list

    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 7, Windows Vista SP2, Windows XP SP3, Windows XP x64 SP2, Windows Server 2008 R2, Windows Server 2008 SP2, Windows Server 2003 SP2

Version Information

F# Runtime

Supported in: 2.0, 4.0

Silverlight

Supported in: 3

See Also

Reference

Collections.List Module (F#)

Microsoft.FSharp.Collections Namespace (F#)