Enumerable.Average<TSource> Method (IEnumerable<TSource>, Func<TSource, Decimal>)
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Computes the average of a sequence of Decimal 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)
Syntax
'Declaration
<ExtensionAttribute> _
Public Shared Function Average(Of TSource) ( _
source As IEnumerable(Of TSource), _
selector As Func(Of TSource, Decimal) _
) As Decimal
public static decimal Average<TSource>(
this IEnumerable<TSource> source,
Func<TSource, decimal> selector
)
Type Parameters
- TSource
The type of the elements of source.
Parameters
- source
Type: System.Collections.Generic.IEnumerable<TSource>
A sequence of values that are used to calculate an average.
- selector
Type: System.Func<TSource, Decimal>
A transform function to apply to each element.
Return Value
Type: System.Decimal
The average of the sequence of values.
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.
Exceptions
Exception | Condition |
---|---|
ArgumentNullException | source or selector is nulla null reference (Nothing in Visual Basic). |
InvalidOperationException | source contains no elements. |
OverflowException | The sum of the elements in the sequence is larger than MaxValue. |
Remarks
In Visual Basic query expression syntax, an Aggregate Into Average() clause translates to an invocation of Average.
Examples
The following code example demonstrates how to use Average<TSource>(IEnumerable<TSource>, Func<TSource, Int64>) to calculate an average.
Note: |
---|
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. |
' Create an array of strings.
Dim numbers() As String = {"10007", "37", "299846234235"}
' Determine the average number after converting each
' string to an Int64 value.
Dim avg As Double = _
numbers.Average(Function(number) Convert.ToInt64(number))
' Display the output.
outputBlock.Text &= "The average is " & avg & vbCrLf
' This code produces the following output:
'
' The average is 99948748093
string[] numbers = { "10007", "37", "299846234235" };
double average = numbers.Average(num => Convert.ToInt64(num));
outputBlock.Text += String.Format("The average is {0}.", average) + "\n";
// This code produces the following output:
//
// The average is 99948748093.
Version Information
Silverlight
Supported in: 5, 4, 3
Silverlight for Windows Phone
Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0
XNA Framework
Supported in: Xbox 360, Windows Phone OS 7.0
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.