Enumerable.Any Enumerable.Any Enumerable.Any Enumerable.Any Method

定义

确定序列中是否包含元素或存在元素满足指定条件。Determines whether any element of a sequence exists or satisfies a condition.

重载

Any<TSource>(IEnumerable<TSource>) Any<TSource>(IEnumerable<TSource>) Any<TSource>(IEnumerable<TSource>) Any<TSource>(IEnumerable<TSource>)

确定序列是否包含任何元素。Determines whether a sequence contains any elements.

Any<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>) Any<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>) Any<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>) Any<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

确定序列中是否存在任意一个元素满足条件。Determines whether any element of a sequence satisfies a condition.

Any<TSource>(IEnumerable<TSource>) Any<TSource>(IEnumerable<TSource>) Any<TSource>(IEnumerable<TSource>) Any<TSource>(IEnumerable<TSource>)

确定序列是否包含任何元素。Determines whether a sequence contains any elements.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static bool Any(System::Collections::Generic::IEnumerable<TSource> ^ source);
public static bool Any<TSource> (this System.Collections.Generic.IEnumerable<TSource> source);
static member Any : seq<'Source> -> bool
<Extension()>
Public Function Any(Of TSource) (source As IEnumerable(Of TSource)) As Boolean

类型参数

TSource

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

参数

source
IEnumerable<TSource>

要检查是否为空的 IEnumerable<T>The IEnumerable<T> to check for emptiness.

返回

如果源序列包含任何元素,则为 true;否则为 falsetrue if the source sequence contains any elements; otherwise, false.

异常

示例

下面的代码示例演示如何使用Any来确定序列是否包含任何元素。The following code example demonstrates how to use Any to determine whether a sequence contains any elements.

List<int> numbers = new List<int> { 1, 2 };
bool hasElements = numbers.Any();

Console.WriteLine("The list {0} empty.",
    hasElements ? "is not" : "is");

// This code produces the following output:
//
// The list is not empty.
' Create a list of Integers.
Dim numbers As New List(Of Integer)(New Integer() {1, 2})

' Determine if the list contains any items.
Dim hasElements As Boolean = numbers.Any()

' Display the output.
Dim text As String = IIf(hasElements, "not ", "")
MsgBox("The list is " & text & "empty.")

' This code produces the following output:
'
' The list is not empty.

Any<TSource>(IEnumerable<TSource>)方法返回的布尔值通常用于where子句的谓词 (Where Where<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>) Visual Basic 中的子句) 或对方法的直接调用。The Boolean value that the Any<TSource>(IEnumerable<TSource>) method returns is typically used in the predicate of a where clause (Where clause in Visual Basic) or a direct call to the Where<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>) method. 下面的示例演示如何使用Any方法。The following example demonstrates this use of the Any method.

class Pet
{
    public string Name { get; set; }
    public int Age { get; set; }
}
class Person
{
    public string LastName { get; set; }
    public Pet[] Pets { get; set; }
}

public static void AnyEx2()
{
    List<Person> people = new List<Person>
        { new Person { LastName = "Haas",
                       Pets = new Pet[] { new Pet { Name="Barley", Age=10 },
                                          new Pet { Name="Boots", Age=14 },
                                          new Pet { Name="Whiskers", Age=6 }}},
          new Person { LastName = "Fakhouri",
                       Pets = new Pet[] { new Pet { Name = "Snowball", Age = 1}}},
          new Person { LastName = "Antebi",
                       Pets = new Pet[] { }},
          new Person { LastName = "Philips",
                       Pets = new Pet[] { new Pet { Name = "Sweetie", Age = 2},
                                          new Pet { Name = "Rover", Age = 13}} }
        };

    // Determine which people have a non-empty Pet array.
    IEnumerable<string> names = from person in people
                                where person.Pets.Any()
                                select person.LastName;

    foreach (string name in names)
    {
        Console.WriteLine(name);
    }

    /* This code produces the following output:
      
       Haas
       Fakhouri
       Philips
    */
}
Structure Pet
    Public Name As String
    Public Age As Integer
End Structure

Structure Person
    Public LastName As String
    Public Pets() As Pet
End Structure

Sub AnyEx2()
    Dim people As New List(Of Person)(New Person() _
{New Person With {.LastName = "Haas",
                  .Pets = New Pet() {New Pet With {.Name = "Barley", .Age = 10},
                                     New Pet With {.Name = "Boots", .Age = 14},
                                     New Pet With {.Name = "Whiskers", .Age = 6}}},
  New Person With {.LastName = "Fakhouri",
                   .Pets = New Pet() {New Pet With {.Name = "Snowball", .Age = 1}}},
  New Person With {.LastName = "Antebi",
                   .Pets = New Pet() {}},
  New Person With {.LastName = "Philips",
                   .Pets = New Pet() {New Pet With {.Name = "Sweetie", .Age = 2},
                                      New Pet With {.Name = "Rover", .Age = 13}}}})

    ' Determine which people have a non-empty Pet array.
    Dim names = From person In people
                Where person.Pets.Any()
                Select person.LastName

    For Each name As String In names
        Console.WriteLine(name)
    Next

    ' This code produces the following output:
    '
    ' Haas
    ' Fakhouri
    ' Philips

End Sub

注解

备注

此方法不返回集合中的任何一个元素,This method does not return any one element of a collection. 相反, 它会确定集合是否包含任何元素。Instead, it determines whether the collection contains any elements.

一旦可以确定source结果, 就会立即停止的枚举。The enumeration of source is stopped as soon as the result can be determined.

在 Visual Basic 查询表达式语法中, Aggregate Into Any()子句转换为对的Any调用。In Visual Basic query expression syntax, an Aggregate Into Any() clause translates to an invocation of Any.

另请参阅

Any<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>) Any<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>) Any<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>) Any<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

确定序列中是否存在任意一个元素满足条件。Determines whether any element of a sequence satisfies a condition.

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

类型参数

TSource

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

参数

source
IEnumerable<TSource>

一个 IEnumerable<T>,其元素将应用谓词。An IEnumerable<T> whose elements to apply the predicate to.

predicate
Func<TSource,Boolean>

用于测试每个元素是否满足条件的函数。A function to test each element for a condition.

返回

如果源序列中存在元素通过了指定谓词中的测试,则为 true;否则为 falsetrue if any elements in the source sequence pass the test in the specified predicate; otherwise, false.

异常

sourcepredicatenullsource or predicate is null.

示例

下面的代码示例演示如何使用Any以确定序列中是否有任意一个元素满足条件。The following code example demonstrates how to use Any to determine whether any element in a sequence satisfies a condition.

class Pet
{
    public string Name { get; set; }
    public int Age { get; set; }
    public bool Vaccinated { get; set; }
}

public static void AnyEx3()
{
    // Create an array of Pets.
    Pet[] pets =
        { new Pet { Name="Barley", Age=8, Vaccinated=true },
          new Pet { Name="Boots", Age=4, Vaccinated=false },
          new Pet { Name="Whiskers", Age=1, Vaccinated=false } };

    // Determine whether any pets over age 1 are also unvaccinated.
    bool unvaccinated =
        pets.Any(p => p.Age > 1 && p.Vaccinated == false);

    Console.WriteLine(
        "There {0} unvaccinated animals over age one.",
        unvaccinated ? "are" : "are not any");
}

// This code produces the following output:
//
//  There are unvaccinated animals over age one.
Structure Pet
    Public Name As String
    Public Age As Integer
    Public Vaccinated As Boolean
End Structure

Shared Sub AnyEx3()
    ' Create a list of Pets
    Dim pets As New List(Of Pet)(New Pet() _
                         {New Pet With {.Name = "Barley", .Age = 8, .Vaccinated = True},
                          New Pet With {.Name = "Boots", .Age = 4, .Vaccinated = False},
                          New Pet With {.Name = "Whiskers", .Age = 1, .Vaccinated = False}})

    ' Determine whether any pets over age 1 are also unvaccinated.
    Dim unvaccinated As Boolean =
pets.Any(Function(pet) pet.Age > 1 And pet.Vaccinated = False)

    ' Display the output.
    Dim text As String = IIf(unvaccinated, "are", "are not")
    MsgBox("There " & text & " unvaccinated animals over age 1.")
End Sub

' This code produces the following output:
'
' There are unvaccinated animals over age 1.

注解

备注

此方法不返回集合中的任何一个元素,This method does not return any one element of a collection. 而是确定集合中是否存在任何元素满足条件。Instead, it determines whether any elements of a collection satisfy a condition.

一旦可以确定source结果, 就会立即停止的枚举。The enumeration of source is stopped as soon as the result can be determined.

在 Visual Basic 查询表达式语法中, Aggregate Into Any()子句转换为对的Any调用。In Visual Basic query expression syntax, an Aggregate Into Any() clause translates to an invocation of Any.

另请参阅

适用于