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

Den Delimarsky|Last Updated: 6/9/2016
|
2 Contributors

Returns the sum of the results 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)

Syntax

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

// Usage:
Array.sumBy projection array

Parameters

projection Type: 'T -> ^U

The function to transform the array elements into the type to be summed.

array Type: 'T[]

The input array.

Return Value

The sum of the results of applying the projection function to each element of the array.

Exceptions

May throw an OverflowException due to arithmetic overflows.

Remarks

The results are summed using the checked + operator and Zero property associated with the summed type.

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

Example

[| 1 .. 10 |]
|> Array.sumBy (fun x -> x * x)
|> printfn "Sum: %d"

Output

385

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

Collections.Array Module (F#)

Microsoft.FSharp.Collections Namespace (F#)

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