Expand Minimize

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

projection

Type: 'T -> ^U

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

list

Type: 'T list

The input list.

Exception

Condition

ArgumentException

Thrown when the list is empty.

The resulting average.

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.

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

Windows 8, Windows 7, Windows Server 2012, Windows Server 2008 R2

F# Core Library Versions

Supported in: 2.0, 4.0, Portable

Was this page helpful?
(1500 characters remaining)
Thank you for your feedback
Show:
© 2014 Microsoft