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

  • Article

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 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.Array Module (F#)

Microsoft.FSharp.Collections Namespace (F#)