List.averageBy<'T,^U> Function (F#)

Returns the average of the elements generated by applying the function to each element of the list.

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

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

// Signature:
List.averageBy : ('T -> ^U) -> 'T list -> ^U (requires ^U with static member (+) and ^U with static member DivideByInt and ^U with static member Zero)

// Usage:
List.averageBy projection list

Parameters

• projection
  Type: 'T -> ^U

  The function to transform the list elements into the type to be averaged.

• list
  Type: 'T list

  The input list.

Exceptions

Return Value

The resulting average.

Remarks

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

Example

The following code example illustrates the use of List.averageBy.

let avg2 = List.averageBy (fun elem -> float elem) [1 .. 10]
printfn "%f" avg2

Output

5.500000

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#)