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MSDN Library

Queryable.Average Method (IQueryable(Of Nullable(Of Int64)))

Computes the average of a sequence of nullable Int64 values.

Namespace:  System.Linq
Assemblies:   System.Linq.Queryable (in System.Linq.Queryable.dll)
  System.Core (in System.Core.dll)

'Declaration
<ExtensionAttribute> _
Public Shared Function Average ( _
	source As IQueryable(Of Nullable(Of Long)) _
) As Nullable(Of Double)

Parameters

source
Type: System.Linq.IQueryable(Of Nullable(Of Int64))

A sequence of nullable Int64 values to calculate the average of.

Return Value

Type: System.Nullable(Of Double)
The average of the sequence of values, or Nothing if the source sequence is empty or contains only Nothing values.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IQueryable(Of Nullable(Of Int64)). 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).

ExceptionCondition
ArgumentNullException

source is Nothing.

The Average(IQueryable(Of Nullable(Of Int64))) method generates a MethodCallExpression that represents calling Average(IQueryable(Of Nullable(Of Int64))) itself. It then passes the MethodCallExpression to the Execute(Of TResult)(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

The query behavior that occurs as a result of executing an expression tree that represents calling Average(IQueryable(Of Nullable(Of Int64))) depends on the implementation of the type of the source parameter. The expected behavior is that it calculates the average of the values in source.

The following code example demonstrates how to use Average(IQueryable(Of Nullable(Of Int64))) to calculate the average of a sequence of values.

        Dim longs() As Nullable(Of Long) = {Nothing, 10007L, 37L, 399846234235L}

        Dim average As Nullable(Of Double) = longs.AsQueryable().Average()

        MsgBox(String.Format("The average is {0}.", average))

        ' This code produces the following output: 
        
        ' The average is 133282081426.333. 

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Portable Class Library

Supported in: Portable Class Library
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