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

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)

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

// Usage:
Array.sumBy projection array


Type: 'T -> ^U

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


Type: 'T []

The input array.

The resulting sum.

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.

The following code shows how to use Array.sumBy.

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



Windows 7, Windows Vista SP2, Windows XP SP3, Windows XP x64 SP2, Windows Server 2008 R2, Windows Server 2008 SP2, Windows Server 2003 SP2

F# Runtime

Supported in: 2.0, 4.0


Supported in: 3

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