Enumerable.Aggregate(TSource, TAccumulate) Method (IEnumerable(TSource), TAccumulate, Func(TAccumulate, TSource, TAccumulate))
Applies an accumulator function over a sequence. The specified seed value is used as the initial accumulator value.
Assembly: System.Core (in System.Core.dll)
Type Parameters
- TSource
The type of the elements of source.
- TAccumulate
The type of the accumulator value.
Parameters
- source
- Type: System.Collections.Generic.IEnumerable(TSource)
An IEnumerable(T) to aggregate over.
- seed
- Type: TAccumulate
The initial accumulator value.
- func
- Type: System.Func(TAccumulate, TSource, TAccumulate)
An accumulator function to be invoked on each element.
Return Value
Type: TAccumulateThe final accumulator value.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable(TSource). When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).| Exception | Condition |
|---|---|
| ArgumentNullException | source or func is a null reference (Nothing in Visual Basic). |
The Aggregate(TSource, TAccumulate)(IEnumerable(TSource), TAccumulate, Func(TAccumulate, TSource, TAccumulate)) method makes it simple to perform a calculation over a sequence of values. This method works by calling func one time for each element in source. Each time func is called, Aggregate(TSource, TAccumulate)(IEnumerable(TSource), TAccumulate, Func(TAccumulate, TSource, TAccumulate)) passes both the element from the sequence and an aggregated value (as the first argument to func). The value of the seed parameter is used as the initial aggregate value. The result of func replaces the previous aggregated value. Aggregate(TSource, TAccumulate)(IEnumerable(TSource), TAccumulate, Func(TAccumulate, TSource, TAccumulate)) returns the final result of func.
To simplify common aggregation operations, the standard query operators also include a general purpose count method, Count, and four numeric aggregation methods, namely Min, Max, Sum, and Average.
Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.