list.map2['t1,'t2,'u]-function-[fsharp].md

title	description	keywords	author	manager	ms.date	ms.topic	ms.prod	ms.technology	ms.assetid
List.map2<'T1,'T2,'U> Function (F#)	List.map2<'T1,'T2,'U> Function (F#)	visual f#, f#, functional programming	dend	danielfe	05/16/2016	language-reference	visual-studio-dev14	devlang-fsharp	aa680673-f521-47b3-bd42-29a526d93904

List.map2<'T1,'T2,'U> Function (F#)

Creates a new list whose elements are the results of applying the given function to the corresponding elements of the two lists pairwise. The lists must have equal lengths.

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

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

Syntax

// Signature:
List.map2 : ('T1 -> 'T2 -> 'U) -> 'T1 list -> 'T2 list -> 'U list

// Usage:
List.map2 mapping list1 list2

Parameters

mapping Type: 'T1 -> 'T2 -> 'U

The function to transform pairs of elements from the input lists.

list1 Type: 'T1list

The first input list.

list2 Type: 'T2list

The second input list.

Return Value

The list of resulting elements.

Exceptions

Exception	Condition
ArgumentException	Thrown when the input lists differ in length.

Remarks

The two lists list1 and list2 must have the same length. If they don't, an exception is thrown.

This function is named Map2 in compiled assemblies. If you are accessing the function from a language other than F#, or through reflection, use this name.

Example

[!code-fsharpMain]

Output

[5; 7; 9]

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

Collections.List Module (F#)

Microsoft.FSharp.Collections Namespace (F#)