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

Creates a new collection whose elements are the results of applying the given function to each of the elements of the collection. The integer index passed to the function indicates the index (from 0) of element being transformed.

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

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

// Signature:
Seq.mapi : (int -> 'T -> 'U) -> seq<'T> -> seq<'U>

// Usage:
Seq.mapi mapping source

Parameters

• mapping
  Type: int -> 'T -> 'U

  A function to transform items from the input sequence that also supplies the current index.

• source
  Type: seq<'T>

  The input sequence.

Exceptions

Exception	Condition
ArgumentNullException	Thrown when the input sequence is null.

Return Value

The result sequence.

Remarks

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

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.Seq Module (F#)

Microsoft.FSharp.Collections Namespace (F#)