Enumerable.Average(Of TSource) Method (IEnumerable(Of TSource), Func(Of TSource, Single))
Computes the average of a sequence of Single values that are obtained by invoking a transform function on each element of the input sequence.
Assembly: System.Core (in System.Core.dll)
'Declaration <ExtensionAttribute> _ Public Shared Function Average(Of TSource) ( _ source As IEnumerable(Of TSource), _ selector As Func(Of TSource, Single) _ ) As Single 'Usage Dim source As IEnumerable(Of TSource) Dim selector As Func(Of TSource, Single) Dim returnValue As Single returnValue = source.Average(selector)
Type Parameters
- TSource
The type of the elements of source.
Parameters
- source
- Type: System.Collections.Generic.IEnumerable(Of TSource)
A sequence of values to calculate the average of.
- selector
- Type: System.Func(Of TSource, Single)
A transform function to apply to each element.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable(Of 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 selector is Nothing. |
| InvalidOperationException | source contains no elements. |
In Visual Basic query expression syntax, an Aggregate Into Average() clause translates to an invocation of Average.
The following code example demonstrates how to use Average(Of TSource)(IEnumerable(Of TSource), Func(Of TSource, Int32)) to calculate an average.
Note: |
|---|
| This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. To extend the example to this topic, change the body of the selector function. |
' Create an array of strings. Dim fruits() As String = _ {"apple", "banana", "mango", "orange", "passionfruit", "grape"} ' Determine the average length of the strings in the array. Dim avg As Double = fruits.Average(Function(s) s.Length) ' Display the output. MsgBox("The average string length is " & avg) ' This code produces the following output: ' ' The average string length is 6.5
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.
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