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Enumerable.Average<TSource> Method (IEnumerable<TSource>, Func<TSource, Int64>)


Computes the average of a sequence of Int64 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 double Average<TSource>(
	this IEnumerable<TSource> source,
	Func<TSource, long> selector


Type: System.Collections.Generic.IEnumerable<TSource>

A sequence of values to calculate the average of.

Type: System.Func<TSourceInt64>

A transform function to apply to each element.

Return Value

Type: System.Double

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<TSource>(IEnumerable<TSource>, Func<TSource, Int64>) to calculate an average.

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. 

Universal Windows Platform
Available since 4.5
.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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