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# Enumerable.Average Method (IEnumerable<Double>)

.NET Framework 4

Computes the average of a sequence of Double values.

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

## Syntax

```public static double Average(
this IEnumerable<double> source
)
```

#### Parameters

source
Type: System.Collections.Generic.IEnumerable<Double>
A sequence of Double values to calculate the average of.

#### Return Value

Type: System.Double
The average of the sequence of values.

#### Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable<Double>. 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).

## Exceptions

ExceptionCondition
ArgumentNullException

source is null.

InvalidOperationException

source contains no elements.

## Remarks

If the sum of the elements is too large to represent as a Double, this method returns positive or negative infinity.

In Visual Basic query expression syntax, an Aggregate Into Average() clause translates to an invocation of Average.

## Examples

The following code example demonstrates how to use Average(IEnumerable<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, substitute the elements of the source sequence with elements of the appropriate numerical type.

```
List<int> grades = new List<int> { 78, 92, 100, 37, 81 };

double average = grades.Average();

Console.WriteLine("The average grade is {0}.", average);

// This code produces the following output:
//
// The average grade is 77.6.

```

## Version Information

#### .NET Framework

Supported in: 4, 3.5

#### .NET Framework Client Profile

Supported in: 4, 3.5 SP1

#### Portable Class Library

Supported in: Portable Class Library

## Platforms

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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