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

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

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

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

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

// Usage:
Array.averageBy projection array

Parameters

• projection
  Type: 'T -> ^U

  The function to transform the array elements before averaging.

• array
  Type: 'T[]

  The input array.

Exceptions

Exception	Condition
ArgumentException	Thrown when array is empty.

Return Value

The computed average.

Remarks

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

Example

The following example illustrates the use of Array.averageBy.

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

Output

5.500000

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.Array Module (F#)

Microsoft.FSharp.Collections Namespace (F#)