EnumerableAverage Method

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Computes the average of a sequence of Decimal values that are obtained by invoking a transform function on each element of the input sequence.

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

public static decimal Average<TSource>(
	this IEnumerable<TSource> source,
	Func<TSource, decimal> selector
generic<typename TSource>
static Decimal Average(
	IEnumerable<TSource>^ source,
	Func<TSource, Decimal>^ selector
static member Average<'TSource> : 
        source:IEnumerable<'TSource> *
        selector:Func<'TSource, decimal> -> decimal
Public Shared Function Average(Of TSource) (
	source As IEnumerable(Of TSource),
	selector As Func(Of TSource, Decimal)
) As Decimal



A sequence of values that are used to calculate an average.


A transform function to apply to each element.

Return Value


The average of the sequence of values.

Type Parameters


The type of the elements of source.

Exception Condition

source or selector is null.


source contains no elements.


The sum of the elements in the sequence is larger than MaxValue.

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 to calculate an average.


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.

string[] numbers = { "10007", "37", "299846234235" };

double average = numbers.Average(num => Convert.ToInt64(num));

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

// This code produces the following output:
// The average is 99948748093. 
' Create an array of strings.
Dim numbers() As String = {"10007", "37", "299846234235"}

' Determine the average number after converting each
' string to an Int64 value.
Dim avg As Double =
numbers.Average(Function(number) Convert.ToInt64(number))

' Display the output.
MsgBox("The average is " & avg)

' This code produces the following output:
' The average is 99948748093
Universal Windows Platform
Available since 8
.NET Framework
Available since 3.5
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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