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

  • Article

Returns the sum of the results generated by applying the function to each element of the sequence.

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

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

// Signature:
Seq.sumBy : ('T -> ^U) -> seq<'T> -> ^U (requires ^U with static member (+) and ^U with static member Zero)

// Usage:
Seq.sumBy projection source

Parameters

  • projection
    Type: 'T -> ^U

    A function to transform items from the input sequence into the quantity that will be summed.

  • source
    Type: seq<'T>

    The input sequence.

Return Value

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

Remarks

The generated elements are summed using the + operator and Zero property associated with the generated 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.

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.Seq Module (F#)

Microsoft.FSharp.Collections Namespace (F#)