Array.mapi2<'T1,'T2,'U> Function (F#)
Builds a new collection whose elements are the results of applying the given function to the corresponding elements of the two collections pairwise, also passing the index of the elements. The two input arrays must have the same lengths, otherwise ArgumentException is raised.
Namespace/Module Path: Microsoft.FSharp.Collections.Array
Assembly: FSharp.Core (in FSharp.Core.dll)
// Signature:
Array.mapi2 : (int -> 'T1 -> 'T2 -> 'U) -> 'T1 [] -> 'T2 [] -> 'U []
// Usage:
Array.mapi2 mapping array1 array2
Parameters
mapping
Type: int -> 'T1 -> 'T2 -> 'UThe function to transform pairs of input elements and their indices.
array1
Type: 'T1 []The first input array.
array2
Type: 'T2 []The second input array.
Exceptions
Exception |
Condition |
|---|---|
Thrown when the input arrays differ in length. |
Return Value
The array of transformed elements.
Remarks
This function is named MapIndexed2 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.mapi2.
let array1 = [| 1; 2; 3 |]
let array2 = [| 4; 5; 6 |]
let arrayAddTimesIndex = Array.mapi2 (fun i x y -> (x + y) * i) array1 array2
printfn "%A" arrayAddTimesIndex
Output
[|0; 7; 18|]
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