Enumerable.Average<TSource> Method (IEnumerable<TSource>, Func<TSource, Single>)
[ 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 Single 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 float Average<TSource>( this IEnumerable<TSource> source, Func<TSource, float> 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, Single>
A transform function to apply to each element.
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. |
| InvalidOperationException | source contains no elements. |
The following code example demonstrates how to use Average<TSource>(IEnumerable<TSource>, Func<TSource, Int32>) 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. |
string[] fruits = { "apple", "banana", "mango", "orange", "passionfruit", "grape" };
double average = fruits.Average(s => s.Length);
outputBlock.Text += String.Format("The average string length is {0}.", average) + "\n";
// This code produces the following output:
//
// The average string length is 6.5.
Note: