Enumerable.Average<TSource> Method (IEnumerable<TSource>, Func<TSource, Nullable<Double>>)
Computes the average of a sequence of nullable Double values that are obtained by invoking a transform function on each element of the input sequence.
Assembly: System.Core (in System.Core.dll)
public static Nullable<double> Average<TSource>( this IEnumerable<TSource> source, Func<TSource, Nullable<double>> selector )
The type of the elements of source.
- Type: System.Collections.Generic.IEnumerable<>
A sequence of values to calculate the average of.
Return ValueType: System.Nullable<Double>
The average of the sequence of values, or null if the source sequence is empty or contains only values that are null.
Usage NoteIn Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable<>. 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).
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.
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.
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.