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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


Type: 'T -> ^U

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


Type: 'T list

The input list.




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



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

F# Core Library Versions

Supported in: 2.0, 4.0, Portable

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