Enumerable.Average<TSource> Method (IEnumerable<TSource>, Func<TSource, Nullable<Double>>)
[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
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 )
Type Parameters
- TSource
The type of the elements of source.
Parameters
- source
- Type: System.Collections.Generic.IEnumerable<TSource>
A sequence of values to calculate the average of.
- selector
- Type: System.Func<TSource, Nullable<Double>>
A transform function to apply to each element.
Return Value
Type: 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 Note
In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable<TSource>. When you use instance method syntax to call this method, omit the first parameter.| Exception | Condition |
|---|---|
| ArgumentNullException | source or selector is null. |
The following code example demonstrates how to use Average<TSource>(IEnumerable<TSource>, Func<TSource, Int64>) to calculate an average.
Note: |
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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. |
Note: