Array.mapi<'T,'U> Function (F#)

  • Article

Builds a new array whose elements are the results of applying the given function to each of the elements of the array. The integer index passed to the function indicates the index of element being transformed.

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

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

// Signature:
Array.mapi : (int -> 'T -> 'U) -> 'T [] -> 'U []

// Usage:
Array.mapi mapping array

Parameters

  • mapping
    Type: int -> 'T -> 'U

    The function to transform elements and their indices.

  • array
    Type: 'T []

    The input array.

Return Value

The array of transformed elements.

Remarks

This function is named MapIndexed 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 demonstrates the use of Array.mapi.

let array1 = [| 1; 2; 3 |]
let newArray = Array.mapi (fun i x -> (i, x)) array1
printfn "%A" newArray

Output

[|(0, 1); (1, 2); (2, 3)|]

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.Array Module (F#)

Microsoft.FSharp.Collections Namespace (F#)