# Queryable.Average Method (IQueryable(Of Nullable(Of Decimal)))

.NET Framework (current version)

Note

The .NET API Reference documentation has a new home. Visit the .NET API Browser on docs.microsoft.com to see the new experience.

Computes the average of a sequence of nullable Decimal values.

Namespace:   System.Linq
Assembly:  System.Core (in System.Core.dll)

## Syntax

```<ExtensionAttribute>
Public Shared Function Average (
source As IQueryable(Of Nullable(Of Decimal))
) As Nullable(Of Decimal)
```

#### Parameters

source
Type:

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

#### Return Value

Type:

The average of the sequence of values, or null if the source sequence is empty or contains only null values.

## Exceptions

Exception Condition
ArgumentNullException

source is null.

## Remarks

The Average(IQueryable(Of Nullable(Of Decimal))) method generates a MethodCallExpression that represents calling Average(IQueryable(Of Nullable(Of Decimal))) 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 Decimal))) 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.

## Examples

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

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, substitute the elements of the source sequence with elements of the appropriate numerical type.

```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.

```

## Version Information

Universal Windows Platform
Available since 8
.NET Framework
Available since 3.5
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.1
Windows Phone
Available since 8.1