Enumerable.Average<TSource> Method (IEnumerable<TSource>, Func<TSource, Int32>)
[ 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 Int32 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 double Average<TSource>( this IEnumerable<TSource> source, Func<TSource, int> 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, Int32>
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. |
| OverflowException | The sum of the elements in the sequence is larger than MaxValue. |
The following code example demonstrates how to use Average<TSource>(IEnumerable<TSource>, Func<TSource, Int32>) to calculate an average.
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.