Enumerable.Average Enumerable.Average Enumerable.Average Enumerable.Average Method

定义

计算数值序列的平均值。Computes the average of a sequence of numeric values.

重载

Average(IEnumerable<Single>) Average(IEnumerable<Single>) Average(IEnumerable<Single>) Average(IEnumerable<Single>)

计算 Single 值序列的平均值。Computes the average of a sequence of Single values.

Average(IEnumerable<Nullable<Single>>) Average(IEnumerable<Nullable<Single>>) Average(IEnumerable<Nullable<Single>>) Average(IEnumerable<Nullable<Single>>)

计算可以为 null 的 Single 值序列的平均值。Computes the average of a sequence of nullable Single values.

Average(IEnumerable<Nullable<Int64>>) Average(IEnumerable<Nullable<Int64>>) Average(IEnumerable<Nullable<Int64>>) Average(IEnumerable<Nullable<Int64>>)

计算可以为 null 的 Int64 值序列的平均值。Computes the average of a sequence of nullable Int64 values.

Average(IEnumerable<Nullable<Int32>>) Average(IEnumerable<Nullable<Int32>>) Average(IEnumerable<Nullable<Int32>>) Average(IEnumerable<Nullable<Int32>>)

计算可以为 null 的 Int32 值序列的平均值。Computes the average of a sequence of nullable Int32 values.

Average(IEnumerable<Nullable<Double>>) Average(IEnumerable<Nullable<Double>>) Average(IEnumerable<Nullable<Double>>) Average(IEnumerable<Nullable<Double>>)

计算可以为 null 的 Double 值序列的平均值。Computes the average of a sequence of nullable Double values.

Average(IEnumerable<Int64>) Average(IEnumerable<Int64>) Average(IEnumerable<Int64>) Average(IEnumerable<Int64>)

计算 Int64 值序列的平均值。Computes the average of a sequence of Int64 values.

Average(IEnumerable<Int32>) Average(IEnumerable<Int32>) Average(IEnumerable<Int32>) Average(IEnumerable<Int32>)

计算 Int32 值序列的平均值。Computes the average of a sequence of Int32 values.

Average(IEnumerable<Double>) Average(IEnumerable<Double>) Average(IEnumerable<Double>) Average(IEnumerable<Double>)

计算 Double 值序列的平均值。Computes the average of a sequence of Double values.

Average(IEnumerable<Decimal>) Average(IEnumerable<Decimal>) Average(IEnumerable<Decimal>) Average(IEnumerable<Decimal>)

计算 Decimal 值序列的平均值。Computes the average of a sequence of Decimal values.

Average(IEnumerable<Nullable<Decimal>>) Average(IEnumerable<Nullable<Decimal>>) Average(IEnumerable<Nullable<Decimal>>) Average(IEnumerable<Nullable<Decimal>>)

计算可以为 null 的 Decimal 值序列的平均值。Computes the average of a sequence of nullable Decimal values.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>)

计算可以为 null 的 Int32 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of nullable Int32 values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Single>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Single>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Single>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Single>)

计算 Single 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of Single values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>)

计算可以为 null 的 Single 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of nullable Single values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>)

计算可以为 null 的 Int64 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of nullable Int64 values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>)

计算可以为 null 的 Double 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。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.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>)

计算可以为 null 的 Decimal 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of nullable Decimal values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Int64>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Int64>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Int64>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)

计算 Int64 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of Int64 values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Int32>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Int32>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Int32>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Int32>)

计算 Int32 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of Int32 values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Double>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Double>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Double>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Double>)

计算 Double 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of Double values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>)

计算 Decimal 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of Decimal values that are obtained by invoking a transform function on each element of the input sequence.

Average(IEnumerable<Single>) Average(IEnumerable<Single>) Average(IEnumerable<Single>) Average(IEnumerable<Single>)

计算 Single 值序列的平均值。Computes the average of a sequence of Single values.

public:
[System::Runtime::CompilerServices::Extension]
 static float Average(System::Collections::Generic::IEnumerable<float> ^ source);
public static float Average (this System.Collections.Generic.IEnumerable<float> source);
static member Average : seq<single> -> single
<Extension()>
Public Function Average (source As IEnumerable(Of Single)) As Single

参数

source
IEnumerable<Single>

要计算其平均值的 Single 值序列。A sequence of Single values to calculate the average of.

返回

值序列的平均值。The average of the sequence of values.

异常

source 中不包含任何元素。source contains no elements.

示例

下面的代码示例演示如何使用Average(IEnumerable<Int32>)计算平均值。The following code example demonstrates how to use Average(IEnumerable<Int32>) to calculate an average.

备注

此代码示例使用此重载方法的重载,该重载与本主题介绍的特定重载不同。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要将此示例扩展到此主题,请将源序列的元素替换为相应数字类型的元素。To extend the example to this topic, substitute the elements of the source sequence with elements of the appropriate numerical type.

List<int> grades = new List<int> { 78, 92, 100, 37, 81 };

double average = grades.Average();

Console.WriteLine("The average grade is {0}.", average);

// This code produces the following output:
//
// The average grade is 77.6.
' Create a list of integers.
Dim grades As New List(Of Integer)(New Integer() {78, 92, 100, 37, 81})

' Determine the average value in the list.
Dim avg As Double = grades.Average()

' Display the output.
MsgBox("The average grade is " & avg)

' This code produces the following output:
'
' The average grade is 77.6

注解

在 Visual Basic 查询表达式语法中,Aggregate Into Average()子句转换为调用AverageIn Visual Basic query expression syntax, an Aggregate Into Average() clause translates to an invocation of Average.

另请参阅

Average(IEnumerable<Nullable<Single>>) Average(IEnumerable<Nullable<Single>>) Average(IEnumerable<Nullable<Single>>) Average(IEnumerable<Nullable<Single>>)

计算可以为 null 的 Single 值序列的平均值。Computes the average of a sequence of nullable Single values.

public:
[System::Runtime::CompilerServices::Extension]
 static Nullable<float> Average(System::Collections::Generic::IEnumerable<Nullable<float>> ^ source);
public static Nullable<float> Average (this System.Collections.Generic.IEnumerable<Nullable<float>> source);
static member Average : seq<Nullable<single>> -> Nullable<single>
<Extension()>
Public Function Average (source As IEnumerable(Of Nullable(Of Single))) As Nullable(Of Single)

参数

source
IEnumerable<Nullable<Single>>

要计算平均值的可以为 null 的 Single 值序列。A sequence of nullable Single values to calculate the average of.

返回

如果源序列为空或仅包含为 null 的值,则为null;否则为值序列的平均值。The average of the sequence of values, or null if the source sequence is empty or contains only values that are null.

异常

示例

下面的代码示例演示如何使用Average(IEnumerable<Nullable<Int64>>)计算平均值。The following code example demonstrates how to use Average(IEnumerable<Nullable<Int64>>) to calculate an average.

备注

此代码示例使用此重载方法的重载,该重载与本主题介绍的特定重载不同。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要将此示例扩展到此主题,请将源序列的元素替换为相应数字类型的元素。To extend the example to this topic, substitute the elements of the source sequence with elements of the appropriate numerical type.

long?[] longs = { null, 10007L, 37L, 399846234235L };

double? average = longs.Average();

Console.WriteLine("The average is {0}.", average);

// This code produces the following output:
//
// The average is 133282081426.333.
' Create an array of nullable long values.
Dim longs() As Nullable(Of Long) = {Nothing, 10007L, 37L, 399846234235L}

' Determine the average value in the array.
Dim avg As Nullable(Of Double) = longs.Average()

' Display the output.
MsgBox("The average is " & avg.ToString)

' This code produces the following output:
'
' The average is 133282081426.333

注解

在 Visual Basic 查询表达式语法中,Aggregate Into Average()子句转换为调用AverageIn Visual Basic query expression syntax, an Aggregate Into Average() clause translates to an invocation of Average.

另请参阅

Average(IEnumerable<Nullable<Int64>>) Average(IEnumerable<Nullable<Int64>>) Average(IEnumerable<Nullable<Int64>>) Average(IEnumerable<Nullable<Int64>>)

计算可以为 null 的 Int64 值序列的平均值。Computes the average of a sequence of nullable Int64 values.

public:
[System::Runtime::CompilerServices::Extension]
 static Nullable<double> Average(System::Collections::Generic::IEnumerable<Nullable<long>> ^ source);
public static Nullable<double> Average (this System.Collections.Generic.IEnumerable<Nullable<long>> source);
static member Average : seq<Nullable<int64>> -> Nullable<double>
<Extension()>
Public Function Average (source As IEnumerable(Of Nullable(Of Long))) As Nullable(Of Double)

参数

source
IEnumerable<Nullable<Int64>>

要计算平均值的可以为 null 的 Int64 值序列。A sequence of nullable Int64 values to calculate the average of.

返回

如果源序列为空或仅包含为 null 的值,则为null;否则为值序列的平均值。The average of the sequence of values, or null if the source sequence is empty or contains only values that are null.

异常

序列中元素的总和大于 MaxValueThe sum of the elements in the sequence is larger than MaxValue.

示例

下面的代码示例演示如何使用Average(IEnumerable<Nullable<Int64>>)计算平均值。The following code example demonstrates how to use Average(IEnumerable<Nullable<Int64>>) to calculate an average.

long?[] longs = { null, 10007L, 37L, 399846234235L };

double? average = longs.Average();

Console.WriteLine("The average is {0}.", average);

// This code produces the following output:
//
// The average is 133282081426.333.
' Create an array of nullable long values.
Dim longs() As Nullable(Of Long) = {Nothing, 10007L, 37L, 399846234235L}

' Determine the average value in the array.
Dim avg As Nullable(Of Double) = longs.Average()

' Display the output.
MsgBox("The average is " & avg.ToString)

' This code produces the following output:
'
' The average is 133282081426.333

注解

在 Visual Basic 查询表达式语法中,Aggregate Into Average()子句转换为调用AverageIn Visual Basic query expression syntax, an Aggregate Into Average() clause translates to an invocation of Average.

另请参阅

Average(IEnumerable<Nullable<Int32>>) Average(IEnumerable<Nullable<Int32>>) Average(IEnumerable<Nullable<Int32>>) Average(IEnumerable<Nullable<Int32>>)

计算可以为 null 的 Int32 值序列的平均值。Computes the average of a sequence of nullable Int32 values.

public:
[System::Runtime::CompilerServices::Extension]
 static Nullable<double> Average(System::Collections::Generic::IEnumerable<Nullable<int>> ^ source);
public static Nullable<double> Average (this System.Collections.Generic.IEnumerable<Nullable<int>> source);
static member Average : seq<Nullable<int>> -> Nullable<double>
<Extension()>
Public Function Average (source As IEnumerable(Of Nullable(Of Integer))) As Nullable(Of Double)

参数

source
IEnumerable<Nullable<Int32>>

要计算平均值的可以为 null 的 Int32 值序列。A sequence of nullable Int32 values to calculate the average of.

返回

如果源序列为空或仅包含为 null 的值,则为null;否则为值序列的平均值。The average of the sequence of values, or null if the source sequence is empty or contains only values that are null.

异常

序列中元素的总和大于 MaxValueThe sum of the elements in the sequence is larger than MaxValue.

示例

下面的代码示例演示如何使用Average(IEnumerable<Nullable<Int64>>)计算平均值。The following code example demonstrates how to use Average(IEnumerable<Nullable<Int64>>) to calculate an average.

备注

此代码示例使用此重载方法的重载,该重载与本主题介绍的特定重载不同。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要将此示例扩展到此主题,请将源序列的元素替换为相应数字类型的元素。To extend the example to this topic, substitute the elements of the source sequence with elements of the appropriate numerical type.

long?[] longs = { null, 10007L, 37L, 399846234235L };

double? average = longs.Average();

Console.WriteLine("The average is {0}.", average);

// This code produces the following output:
//
// The average is 133282081426.333.
' Create an array of nullable long values.
Dim longs() As Nullable(Of Long) = {Nothing, 10007L, 37L, 399846234235L}

' Determine the average value in the array.
Dim avg As Nullable(Of Double) = longs.Average()

' Display the output.
MsgBox("The average is " & avg.ToString)

' This code produces the following output:
'
' The average is 133282081426.333

注解

在 Visual Basic 查询表达式语法中,Aggregate Into Average()子句转换为调用AverageIn Visual Basic query expression syntax, an Aggregate Into Average() clause translates to an invocation of Average.

另请参阅

Average(IEnumerable<Nullable<Double>>) Average(IEnumerable<Nullable<Double>>) Average(IEnumerable<Nullable<Double>>) Average(IEnumerable<Nullable<Double>>)

计算可以为 null 的 Double 值序列的平均值。Computes the average of a sequence of nullable Double values.

public:
[System::Runtime::CompilerServices::Extension]
 static Nullable<double> Average(System::Collections::Generic::IEnumerable<Nullable<double>> ^ source);
public static Nullable<double> Average (this System.Collections.Generic.IEnumerable<Nullable<double>> source);
static member Average : seq<Nullable<double>> -> Nullable<double>
<Extension()>
Public Function Average (source As IEnumerable(Of Nullable(Of Double))) As Nullable(Of Double)

参数

source
IEnumerable<Nullable<Double>>

要计算平均值的可以为 null 的 Double 值序列。A sequence of nullable Double values to calculate the average of.

返回

如果源序列为空或仅包含为 null 的值,则为null;否则为值序列的平均值。The average of the sequence of values, or null if the source sequence is empty or contains only values that are null.

异常

示例

下面的代码示例演示如何使用Average(IEnumerable<Nullable<Int64>>)计算平均值。The following code example demonstrates how to use Average(IEnumerable<Nullable<Int64>>) to calculate an average.

备注

此代码示例使用此重载方法的重载,该重载与本主题介绍的特定重载不同。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要将此示例扩展到此主题,请将源序列的元素替换为相应数字类型的元素。To extend the example to this topic, substitute the elements of the source sequence with elements of the appropriate numerical type.

long?[] longs = { null, 10007L, 37L, 399846234235L };

double? average = longs.Average();

Console.WriteLine("The average is {0}.", average);

// This code produces the following output:
//
// The average is 133282081426.333.
' Create an array of nullable long values.
Dim longs() As Nullable(Of Long) = {Nothing, 10007L, 37L, 399846234235L}

' Determine the average value in the array.
Dim avg As Nullable(Of Double) = longs.Average()

' Display the output.
MsgBox("The average is " & avg.ToString)

' This code produces the following output:
'
' The average is 133282081426.333

注解

如果元素的总和是太大,无法表示为Double,此方法将返回正或负无穷大。If the sum of the elements is too large to represent as a Double, this method returns positive or negative infinity.

在 Visual Basic 查询表达式语法中,Aggregate Into Average()子句转换为调用AverageIn Visual Basic query expression syntax, an Aggregate Into Average() clause translates to an invocation of Average.

另请参阅

Average(IEnumerable<Int64>) Average(IEnumerable<Int64>) Average(IEnumerable<Int64>) Average(IEnumerable<Int64>)

计算 Int64 值序列的平均值。Computes the average of a sequence of Int64 values.

public:
[System::Runtime::CompilerServices::Extension]
 static double Average(System::Collections::Generic::IEnumerable<long> ^ source);
public static double Average (this System.Collections.Generic.IEnumerable<long> source);
static member Average : seq<int64> -> double
<Extension()>
Public Function Average (source As IEnumerable(Of Long)) As Double

参数

source
IEnumerable<Int64>

要计算其平均值的 Int64 值序列。A sequence of Int64 values to calculate the average of.

返回

值序列的平均值。The average of the sequence of values.

异常

source 中不包含任何元素。source contains no elements.

示例

下面的代码示例演示如何使用Average(IEnumerable<Int32>)计算平均值。The following code example demonstrates how to use Average(IEnumerable<Int32>) to calculate an average.

备注

此代码示例使用此重载方法的重载,该重载与本主题介绍的特定重载不同。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要将此示例扩展到此主题,请将源序列的元素替换为相应数字类型的元素。To extend the example to this topic, substitute the elements of the source sequence with elements of the appropriate numerical type.

List<int> grades = new List<int> { 78, 92, 100, 37, 81 };

double average = grades.Average();

Console.WriteLine("The average grade is {0}.", average);

// This code produces the following output:
//
// The average grade is 77.6.
' Create a list of integers.
Dim grades As New List(Of Integer)(New Integer() {78, 92, 100, 37, 81})

' Determine the average value in the list.
Dim avg As Double = grades.Average()

' Display the output.
MsgBox("The average grade is " & avg)

' This code produces the following output:
'
' The average grade is 77.6

注解

在 Visual Basic 查询表达式语法中,Aggregate Into Average()子句转换为调用AverageIn Visual Basic query expression syntax, an Aggregate Into Average() clause translates to an invocation of Average.

另请参阅

Average(IEnumerable<Int32>) Average(IEnumerable<Int32>) Average(IEnumerable<Int32>) Average(IEnumerable<Int32>)

计算 Int32 值序列的平均值。Computes the average of a sequence of Int32 values.

public:
[System::Runtime::CompilerServices::Extension]
 static double Average(System::Collections::Generic::IEnumerable<int> ^ source);
public static double Average (this System.Collections.Generic.IEnumerable<int> source);
static member Average : seq<int> -> double
<Extension()>
Public Function Average (source As IEnumerable(Of Integer)) As Double

参数

source
IEnumerable<Int32>

要计算其平均值的 Int32 值序列。A sequence of Int32 values to calculate the average of.

返回

值序列的平均值。The average of the sequence of values.

异常

source 中不包含任何元素。source contains no elements.

示例

下面的代码示例演示如何使用Average(IEnumerable<Int32>)计算平均值。The following code example demonstrates how to use Average(IEnumerable<Int32>) to calculate an average.

List<int> grades = new List<int> { 78, 92, 100, 37, 81 };

double average = grades.Average();

Console.WriteLine("The average grade is {0}.", average);

// This code produces the following output:
//
// The average grade is 77.6.
' Create a list of integers.
Dim grades As New List(Of Integer)(New Integer() {78, 92, 100, 37, 81})

' Determine the average value in the list.
Dim avg As Double = grades.Average()

' Display the output.
MsgBox("The average grade is " & avg)

' This code produces the following output:
'
' The average grade is 77.6

注解

在 Visual Basic 查询表达式语法中,Aggregate Into Average()子句转换为调用AverageIn Visual Basic query expression syntax, an Aggregate Into Average() clause translates to an invocation of Average.

另请参阅

Average(IEnumerable<Double>) Average(IEnumerable<Double>) Average(IEnumerable<Double>) Average(IEnumerable<Double>)

计算 Double 值序列的平均值。Computes the average of a sequence of Double values.

public:
[System::Runtime::CompilerServices::Extension]
 static double Average(System::Collections::Generic::IEnumerable<double> ^ source);
public static double Average (this System.Collections.Generic.IEnumerable<double> source);
static member Average : seq<double> -> double
<Extension()>
Public Function Average (source As IEnumerable(Of Double)) As Double

参数

source
IEnumerable<Double>

要计算其平均值的 Double 值序列。A sequence of Double values to calculate the average of.

返回

值序列的平均值。The average of the sequence of values.

异常

source 中不包含任何元素。source contains no elements.

示例

下面的代码示例演示如何使用Average(IEnumerable<Int32>)计算平均值。The following code example demonstrates how to use Average(IEnumerable<Int32>) to calculate an average.

备注

此代码示例使用此重载方法的重载,该重载与本主题介绍的特定重载不同。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要将此示例扩展到此主题,请将源序列的元素替换为相应数字类型的元素。To extend the example to this topic, substitute the elements of the source sequence with elements of the appropriate numerical type.

List<int> grades = new List<int> { 78, 92, 100, 37, 81 };

double average = grades.Average();

Console.WriteLine("The average grade is {0}.", average);

// This code produces the following output:
//
// The average grade is 77.6.
' Create a list of integers.
Dim grades As New List(Of Integer)(New Integer() {78, 92, 100, 37, 81})

' Determine the average value in the list.
Dim avg As Double = grades.Average()

' Display the output.
MsgBox("The average grade is " & avg)

' This code produces the following output:
'
' The average grade is 77.6

注解

如果元素的总和是太大,无法表示为Double,此方法将返回正或负无穷大。If the sum of the elements is too large to represent as a Double, this method returns positive or negative infinity.

在 Visual Basic 查询表达式语法中,Aggregate Into Average()子句转换为调用AverageIn Visual Basic query expression syntax, an Aggregate Into Average() clause translates to an invocation of Average.

另请参阅

Average(IEnumerable<Decimal>) Average(IEnumerable<Decimal>) Average(IEnumerable<Decimal>) Average(IEnumerable<Decimal>)

计算 Decimal 值序列的平均值。Computes the average of a sequence of Decimal values.

public:
[System::Runtime::CompilerServices::Extension]
 static System::Decimal Average(System::Collections::Generic::IEnumerable<System::Decimal> ^ source);
public static decimal Average (this System.Collections.Generic.IEnumerable<decimal> source);
static member Average : seq<decimal> -> decimal
<Extension()>
Public Function Average (source As IEnumerable(Of Decimal)) As Decimal

参数

source
IEnumerable<Decimal>

要计算其平均值的 Decimal 值序列。A sequence of Decimal values to calculate the average of.

返回

值序列的平均值。The average of the sequence of values.

异常

source 中不包含任何元素。source contains no elements.

示例

下面的代码示例演示如何使用Average(IEnumerable<Int32>)要计算平均值的一系列值。The following code example demonstrates how to use Average(IEnumerable<Int32>) to calculate the average of a sequence of values.

备注

此代码示例使用此重载方法的重载,该重载与本主题介绍的特定重载不同。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要将此示例扩展到此主题,请将源序列的元素替换为相应数字类型的元素。To extend the example to this topic, substitute the elements of the source sequence with elements of the appropriate numerical type.

List<int> grades = new List<int> { 78, 92, 100, 37, 81 };

double average = grades.Average();

Console.WriteLine("The average grade is {0}.", average);

// This code produces the following output:
//
// The average grade is 77.6.
' Create a list of integers.
Dim grades As New List(Of Integer)(New Integer() {78, 92, 100, 37, 81})

' Determine the average value in the list.
Dim avg As Double = grades.Average()

' Display the output.
MsgBox("The average grade is " & avg)

' This code produces the following output:
'
' The average grade is 77.6

注解

在 Visual Basic 查询表达式语法中,Aggregate Into Average()子句转换为调用AverageIn Visual Basic query expression syntax, an Aggregate Into Average() clause translates to an invocation of Average.

另请参阅

Average(IEnumerable<Nullable<Decimal>>) Average(IEnumerable<Nullable<Decimal>>) Average(IEnumerable<Nullable<Decimal>>) Average(IEnumerable<Nullable<Decimal>>)

计算可以为 null 的 Decimal 值序列的平均值。Computes the average of a sequence of nullable Decimal values.

public:
[System::Runtime::CompilerServices::Extension]
 static Nullable<System::Decimal> Average(System::Collections::Generic::IEnumerable<Nullable<System::Decimal>> ^ source);
public static Nullable<decimal> Average (this System.Collections.Generic.IEnumerable<Nullable<decimal>> source);
static member Average : seq<Nullable<decimal>> -> Nullable<decimal>
<Extension()>
Public Function Average (source As IEnumerable(Of Nullable(Of Decimal))) As Nullable(Of Decimal)

参数

source
IEnumerable<Nullable<Decimal>>

要计算平均值的可以为 null 的 Decimal 值序列。A sequence of nullable Decimal values to calculate the average of.

返回

如果源序列为空或仅包含为 null 的值,则为null;否则为值序列的平均值。The average of the sequence of values, or null if the source sequence is empty or contains only values that are null.

异常

序列中元素的总和大于 MaxValueThe sum of the elements in the sequence is larger than MaxValue.

示例

下面的代码示例演示如何使用Average(IEnumerable<Nullable<Int64>>)计算平均值。The following code example demonstrates how to use Average(IEnumerable<Nullable<Int64>>) to calculate an average.

备注

此代码示例使用此重载方法的重载,该重载与本主题介绍的特定重载不同。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要将此示例扩展到此主题,请将源序列的元素替换为相应数字类型的元素。To extend the example to this topic, substitute the elements of the source sequence with elements of the appropriate numerical type.

long?[] longs = { null, 10007L, 37L, 399846234235L };

double? average = longs.Average();

Console.WriteLine("The average is {0}.", average);

// This code produces the following output:
//
// The average is 133282081426.333.
' Create an array of nullable long values.
Dim longs() As Nullable(Of Long) = {Nothing, 10007L, 37L, 399846234235L}

' Determine the average value in the array.
Dim avg As Nullable(Of Double) = longs.Average()

' Display the output.
MsgBox("The average is " & avg.ToString)

' This code produces the following output:
'
' The average is 133282081426.333

注解

在 Visual Basic 查询表达式语法中,Aggregate Into Average()子句转换为调用AverageIn Visual Basic query expression syntax, an Aggregate Into Average() clause translates to an invocation of Average.

另请参阅

Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>)

计算可以为 null 的 Int32 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of nullable Int32 values that are obtained by invoking a transform function on each element of the input sequence.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static Nullable<double> Average(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, Nullable<int>> ^ selector);
public static Nullable<double> Average<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,Nullable<int>> selector);
static member Average : seq<'Source> * Func<'Source, Nullable<int>> -> Nullable<double>
<Extension()>
Public Function Average(Of TSource) (source As IEnumerable(Of TSource), selector As Func(Of TSource, Nullable(Of Integer))) As Nullable(Of Double)

类型参数

TSource

source 的元素类型。The type of the elements of source.

参数

source
IEnumerable<TSource>

要计算其平均值的值序列。A sequence of values to calculate the average of.

selector
Func<TSource,Nullable<Int32>>

应用于每个元素的转换函数。A transform function to apply to each element.

返回

如果源序列为空或仅包含为 null 的值,则为null;否则为值序列的平均值。The average of the sequence of values, or null if the source sequence is empty or contains only values that are null.

异常

sourceselectornullsource or selector is null.

序列中元素的总和大于 MaxValueThe sum of the elements in the sequence is larger than MaxValue.

示例

下面的代码示例演示如何使用Average<TSource>(IEnumerable<TSource>, Func<TSource,Int32>)计算平均值。The following code example demonstrates how to use Average<TSource>(IEnumerable<TSource>, Func<TSource,Int32>) to calculate an average.

备注

此代码示例使用此重载方法的重载,该重载与本主题介绍的特定重载不同。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要将此示例扩展到本主题,请更改 selector 函数体。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);

Console.WriteLine("The average string length is {0}.", average);

// This code produces the following output:
//
// The average string length is 6.5.
' Create an array of strings.
Dim fruits() As String =
{"apple", "banana", "mango", "orange", "passionfruit", "grape"}

' Determine the average length of the strings in the array.
Dim avg As Double = fruits.Average(Function(s) s.Length)

' Display the output.
MsgBox("The average string length is " & avg)

' This code produces the following output:
'
' The average string length is 6.5

注解

在 Visual Basic 查询表达式语法中,Aggregate Into Average()子句转换为调用AverageIn Visual Basic query expression syntax, an Aggregate Into Average() clause translates to an invocation of Average.

另请参阅

Average<TSource>(IEnumerable<TSource>, Func<TSource,Single>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Single>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Single>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Single>)

计算 Single 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of Single values that are obtained by invoking a transform function on each element of the input sequence.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static float Average(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, float> ^ selector);
public static float Average<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,float> selector);
static member Average : seq<'Source> * Func<'Source, single> -> single
<Extension()>
Public Function Average(Of TSource) (source As IEnumerable(Of TSource), selector As Func(Of TSource, Single)) As Single

类型参数

TSource

source 的元素类型。The type of the elements of source.

参数

source
IEnumerable<TSource>

要计算其平均值的值序列。A sequence of values to calculate the average of.

selector
Func<TSource,Single>

应用于每个元素的转换函数。A transform function to apply to each element.

返回

值序列的平均值。The average of the sequence of values.

异常

sourceselectornullsource or selector is null.

source 中不包含任何元素。source contains no elements.

示例

下面的代码示例演示如何使用Average<TSource>(IEnumerable<TSource>, Func<TSource,Int32>)计算平均值。The following code example demonstrates how to use Average<TSource>(IEnumerable<TSource>, Func<TSource,Int32>) to calculate an average.

备注

此代码示例使用此重载方法的重载,该重载与本主题介绍的特定重载不同。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要将此示例扩展到本主题,请更改 selector 函数体。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);

Console.WriteLine("The average string length is {0}.", average);

// This code produces the following output:
//
// The average string length is 6.5.
' Create an array of strings.
Dim fruits() As String =
{"apple", "banana", "mango", "orange", "passionfruit", "grape"}

' Determine the average length of the strings in the array.
Dim avg As Double = fruits.Average(Function(s) s.Length)

' Display the output.
MsgBox("The average string length is " & avg)

' This code produces the following output:
'
' The average string length is 6.5

注解

在 Visual Basic 查询表达式语法中,Aggregate Into Average()子句转换为调用AverageIn Visual Basic query expression syntax, an Aggregate Into Average() clause translates to an invocation of Average.

另请参阅

Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>)

计算可以为 null 的 Single 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of nullable Single values that are obtained by invoking a transform function on each element of the input sequence.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static Nullable<float> Average(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, Nullable<float>> ^ selector);
public static Nullable<float> Average<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,Nullable<float>> selector);
static member Average : seq<'Source> * Func<'Source, Nullable<single>> -> Nullable<single>
<Extension()>
Public Function Average(Of TSource) (source As IEnumerable(Of TSource), selector As Func(Of TSource, Nullable(Of Single))) As Nullable(Of Single)

类型参数

TSource

source 的元素类型。The type of the elements of source.

参数

source
IEnumerable<TSource>

要计算其平均值的值序列。A sequence of values to calculate the average of.

selector
Func<TSource,Nullable<Single>>

应用于每个元素的转换函数。A transform function to apply to each element.

返回

如果源序列为空或仅包含为 null 的值,则为null;否则为值序列的平均值。The average of the sequence of values, or null if the source sequence is empty or contains only values that are null.

异常

sourceselectornullsource or selector is null.

示例

下面的代码示例演示如何使用Average<TSource>(IEnumerable<TSource>, Func<TSource,Int32>)计算平均值。The following code example demonstrates how to use Average<TSource>(IEnumerable<TSource>, Func<TSource,Int32>) to calculate an average.

备注

此代码示例使用此重载方法的重载,该重载与本主题介绍的特定重载不同。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要将此示例扩展到本主题,请更改 selector 函数体。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);

Console.WriteLine("The average string length is {0}.", average);

// This code produces the following output:
//
// The average string length is 6.5.
' Create an array of strings.
Dim fruits() As String =
{"apple", "banana", "mango", "orange", "passionfruit", "grape"}

' Determine the average length of the strings in the array.
Dim avg As Double = fruits.Average(Function(s) s.Length)

' Display the output.
MsgBox("The average string length is " & avg)

' This code produces the following output:
'
' The average string length is 6.5

注解

在 Visual Basic 查询表达式语法中,Aggregate Into Average()子句转换为调用AverageIn Visual Basic query expression syntax, an Aggregate Into Average() clause translates to an invocation of Average.

另请参阅

Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>)

计算可以为 null 的 Int64 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of nullable Int64 values that are obtained by invoking a transform function on each element of the input sequence.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static Nullable<double> Average(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, Nullable<long>> ^ selector);
public static Nullable<double> Average<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,Nullable<long>> selector);
static member Average : seq<'Source> * Func<'Source, Nullable<int64>> -> Nullable<double>
<Extension()>
Public Function Average(Of TSource) (source As IEnumerable(Of TSource), selector As Func(Of TSource, Nullable(Of Long))) As Nullable(Of Double)

类型参数

TSource

source 的元素类型。The type of the elements of source.

参数

source
IEnumerable<TSource>

要计算其平均值的值序列。A sequence of values to calculate the average of.

selector
Func<TSource,Nullable<Int64>>

应用于每个元素的转换函数。A transform function to apply to each element.

返回

如果源序列为空或仅包含为 null 的值,则为null;否则为值序列的平均值。The average of the sequence of values, or null if the source sequence is empty or contains only values that are null.

示例

下面的代码示例演示如何使用Average<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)计算平均值。The following code example demonstrates how to use Average<TSource>(IEnumerable<TSource>, Func<TSource,Int64>) to calculate an average.

备注

此代码示例使用此重载方法的重载,该重载与本主题介绍的特定重载不同。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要将此示例扩展到本主题,请更改 selector 函数体。To extend the example to this topic, change the body of the selector function.

string[] numbers = { "10007", "37", "299846234235" };

double average = numbers.Average(num => Convert.ToInt64(num));

Console.WriteLine("The average is {0}.", average);

// This code produces the following output:
//
// The average is 99948748093.
' 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.
MsgBox("The average is " & avg)

' This code produces the following output:
'
' The average is 99948748093

注解

在 Visual Basic 查询表达式语法中,Aggregate Into Average()子句转换为调用AverageIn Visual Basic query expression syntax, an Aggregate Into Average() clause translates to an invocation of Average.

另请参阅

Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>)

计算可以为 null 的 Double 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。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.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static Nullable<double> Average(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, Nullable<double>> ^ selector);
public static Nullable<double> Average<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,Nullable<double>> selector);
static member Average : seq<'Source> * Func<'Source, Nullable<double>> -> Nullable<double>
<Extension()>
Public Function Average(Of TSource) (source As IEnumerable(Of TSource), selector As Func(Of TSource, Nullable(Of Double))) As Nullable(Of Double)

类型参数

TSource

source 的元素类型。The type of the elements of source.

参数

source
IEnumerable<TSource>

要计算其平均值的值序列。A sequence of values to calculate the average of.

selector
Func<TSource,Nullable<Double>>

应用于每个元素的转换函数。A transform function to apply to each element.

返回

如果源序列为空或仅包含为 null 的值,则为null;否则为值序列的平均值。The average of the sequence of values, or null if the source sequence is empty or contains only values that are null.

异常

sourceselectornullsource or selector is null.

示例

下面的代码示例演示如何使用Average<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)计算平均值。The following code example demonstrates how to use Average<TSource>(IEnumerable<TSource>, Func<TSource,Int64>) to calculate an average.

备注

此代码示例使用此重载方法的重载,该重载与本主题介绍的特定重载不同。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要将此示例扩展到本主题,请更改 selector 函数体。To extend the example to this topic, change the body of the selector function.

string[] numbers = { "10007", "37", "299846234235" };

double average = numbers.Average(num => Convert.ToInt64(num));

Console.WriteLine("The average is {0}.", average);

// This code produces the following output:
//
// The average is 99948748093.
' 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.
MsgBox("The average is " & avg)

' This code produces the following output:
'
' The average is 99948748093

注解

在 Visual Basic 查询表达式语法中,Aggregate Into Average()子句转换为调用AverageIn Visual Basic query expression syntax, an Aggregate Into Average() clause translates to an invocation of Average.

另请参阅

Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>)

计算可以为 null 的 Decimal 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of nullable Decimal values that are obtained by invoking a transform function on each element of the input sequence.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static Nullable<System::Decimal> Average(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, Nullable<System::Decimal>> ^ selector);
public static Nullable<decimal> Average<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,Nullable<decimal>> selector);
static member Average : seq<'Source> * Func<'Source, Nullable<decimal>> -> Nullable<decimal>
<Extension()>
Public Function Average(Of TSource) (source As IEnumerable(Of TSource), selector As Func(Of TSource, Nullable(Of Decimal))) As Nullable(Of Decimal)

类型参数

TSource

source 的元素类型。The type of the elements of source.

参数

source
IEnumerable<TSource>

要计算其平均值的值序列。A sequence of values to calculate the average of.

selector
Func<TSource,Nullable<Decimal>>

应用于每个元素的转换函数。A transform function to apply to each element.

返回

如果源序列为空或仅包含为 null 的值,则为null;否则为值序列的平均值。The average of the sequence of values, or null if the source sequence is empty or contains only values that are null.

异常

sourceselectornullsource or selector is null.

序列中元素的总和大于 MaxValueThe sum of the elements in the sequence is larger than MaxValue.

示例

下面的代码示例演示如何使用Average<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)计算平均值。The following code example demonstrates how to use Average<TSource>(IEnumerable<TSource>, Func<TSource,Int64>) to calculate an average.

备注

此代码示例使用此重载方法的重载,该重载与本主题介绍的特定重载不同。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要将此示例扩展到本主题,请更改 selector 函数体。To extend the example to this topic, change the body of the selector function.

string[] numbers = { "10007", "37", "299846234235" };

double average = numbers.Average(num => Convert.ToInt64(num));

Console.WriteLine("The average is {0}.", average);

// This code produces the following output:
//
// The average is 99948748093.
' 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.
MsgBox("The average is " & avg)

' This code produces the following output:
'
' The average is 99948748093

注解

在 Visual Basic 查询表达式语法中,Aggregate Into Average()子句转换为调用AverageIn Visual Basic query expression syntax, an Aggregate Into Average() clause translates to an invocation of Average.

另请参阅

Average<TSource>(IEnumerable<TSource>, Func<TSource,Int64>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Int64>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Int64>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)

计算 Int64 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of Int64 values that are obtained by invoking a transform function on each element of the input sequence.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static double Average(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, long> ^ selector);
public static double Average<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,long> selector);
static member Average : seq<'Source> * Func<'Source, int64> -> double
<Extension()>
Public Function Average(Of TSource) (source As IEnumerable(Of TSource), selector As Func(Of TSource, Long)) As Double

类型参数

TSource

源的元素的类型。The type of the elements of source.

参数

source
IEnumerable<TSource>

要计算其平均值的值序列。A sequence of values to calculate the average of.

selector
Func<TSource,Int64>

应用于每个元素的转换函数。A transform function to apply to each element.

返回

值序列的平均值。The average of the sequence of values.

异常

sourceselectornullsource or selector is null.

source 中不包含任何元素。source contains no elements.

序列中元素的总和大于 MaxValueThe sum of the elements in the sequence is larger than MaxValue.

示例

下面的代码示例演示如何使用Average<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)计算平均值。The following code example demonstrates how to use Average<TSource>(IEnumerable<TSource>, Func<TSource,Int64>) to calculate an average.

string[] numbers = { "10007", "37", "299846234235" };

double average = numbers.Average(num => Convert.ToInt64(num));

Console.WriteLine("The average is {0}.", average);

// This code produces the following output:
//
// The average is 99948748093.
' 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.
MsgBox("The average is " & avg)

' This code produces the following output:
'
' The average is 99948748093

注解

在 Visual Basic 查询表达式语法中,Aggregate Into Average()子句转换为调用AverageIn Visual Basic query expression syntax, an Aggregate Into Average() clause translates to an invocation of Average.

另请参阅

Average<TSource>(IEnumerable<TSource>, Func<TSource,Int32>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Int32>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Int32>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Int32>)

计算 Int32 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of Int32 values that are obtained by invoking a transform function on each element of the input sequence.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static double Average(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, int> ^ selector);
public static double Average<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,int> selector);
static member Average : seq<'Source> * Func<'Source, int> -> double
<Extension()>
Public Function Average(Of TSource) (source As IEnumerable(Of TSource), selector As Func(Of TSource, Integer)) As Double

类型参数

TSource

source 的元素类型。The type of the elements of source.

参数

source
IEnumerable<TSource>

要计算其平均值的值序列。A sequence of values to calculate the average of.

selector
Func<TSource,Int32>

应用于每个元素的转换函数。A transform function to apply to each element.

返回

值序列的平均值。The average of the sequence of values.

异常

sourceselectornullsource or selector is null.

source 中不包含任何元素。source contains no elements.

序列中元素的总和大于 MaxValueThe sum of the elements in the sequence is larger than MaxValue.

示例

下面的代码示例演示如何使用Average<TSource>(IEnumerable<TSource>, Func<TSource,Int32>)计算平均值。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);

Console.WriteLine("The average string length is {0}.", average);

// This code produces the following output:
//
// The average string length is 6.5.
' Create an array of strings.
Dim fruits() As String =
{"apple", "banana", "mango", "orange", "passionfruit", "grape"}

' Determine the average length of the strings in the array.
Dim avg As Double = fruits.Average(Function(s) s.Length)

' Display the output.
MsgBox("The average string length is " & avg)

' This code produces the following output:
'
' The average string length is 6.5

注解

在 Visual Basic 查询表达式语法中,Aggregate Into Average()子句转换为调用AverageIn Visual Basic query expression syntax, an Aggregate Into Average() clause translates to an invocation of Average.

另请参阅

Average<TSource>(IEnumerable<TSource>, Func<TSource,Double>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Double>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Double>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Double>)

计算 Double 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of Double values that are obtained by invoking a transform function on each element of the input sequence.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static double Average(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, double> ^ selector);
public static double Average<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,double> selector);
static member Average : seq<'Source> * Func<'Source, double> -> double
<Extension()>
Public Function Average(Of TSource) (source As IEnumerable(Of TSource), selector As Func(Of TSource, Double)) As Double

类型参数

TSource

source 的元素类型。The type of the elements of source.

参数

source
IEnumerable<TSource>

要计算其平均值的值序列。A sequence of values to calculate the average of.

selector
Func<TSource,Double>

应用于每个元素的转换函数。A transform function to apply to each element.

返回

值序列的平均值。The average of the sequence of values.

异常

sourceselectornullsource or selector is null.

source 中不包含任何元素。source contains no elements.

示例

下面的代码示例演示如何使用Average<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)计算平均值。The following code example demonstrates how to use Average<TSource>(IEnumerable<TSource>, Func<TSource,Int64>) to calculate an average.

备注

此代码示例使用此重载方法的重载,该重载与本主题介绍的特定重载不同。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要将此示例扩展到本主题,请更改 selector 函数体。To extend the example to this topic, change the body of the selector function.

string[] numbers = { "10007", "37", "299846234235" };

double average = numbers.Average(num => Convert.ToInt64(num));

Console.WriteLine("The average is {0}.", average);

// This code produces the following output:
//
// The average is 99948748093.
' 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.
MsgBox("The average is " & avg)

' This code produces the following output:
'
' The average is 99948748093

注解

在 Visual Basic 查询表达式语法中,Aggregate Into Average()子句转换为调用AverageIn Visual Basic query expression syntax, an Aggregate Into Average() clause translates to an invocation of Average.

另请参阅

Average<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>) Average<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>)

计算 Decimal 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of Decimal values that are obtained by invoking a transform function on each element of the input sequence.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static System::Decimal Average(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, System::Decimal> ^ selector);
public static decimal Average<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,decimal> selector);
static member Average : seq<'Source> * Func<'Source, decimal> -> decimal
<Extension()>
Public Function Average(Of TSource) (source As IEnumerable(Of TSource), selector As Func(Of TSource, Decimal)) As Decimal

类型参数

TSource

source 的元素类型。The type of the elements of source.

参数

source
IEnumerable<TSource>

用于计算平均值的值序列。A sequence of values that are used to calculate an average.

selector
Func<TSource,Decimal>

应用于每个元素的转换函数。A transform function to apply to each element.

返回

值序列的平均值。The average of the sequence of values.

异常

sourceselectornullsource or selector is null.

source 中不包含任何元素。source contains no elements.

序列中元素的总和大于 MaxValueThe sum of the elements in the sequence is larger than MaxValue.

示例

下面的代码示例演示如何使用Average<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)计算平均值。The following code example demonstrates how to use Average<TSource>(IEnumerable<TSource>, Func<TSource,Int64>) to calculate an average.

备注

此代码示例使用此重载方法的重载,该重载与本主题介绍的特定重载不同。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要将此示例扩展到本主题,请更改 selector 函数体。To extend the example to this topic, change the body of the selector function.

string[] numbers = { "10007", "37", "299846234235" };

double average = numbers.Average(num => Convert.ToInt64(num));

Console.WriteLine("The average is {0}.", average);

// This code produces the following output:
//
// The average is 99948748093.
' 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.
MsgBox("The average is " & avg)

' This code produces the following output:
'
' The average is 99948748093

注解

在 Visual Basic 查询表达式语法中,Aggregate Into Average()子句转换为调用AverageIn Visual Basic query expression syntax, an Aggregate Into Average() clause translates to an invocation of Average.

另请参阅

适用于