Enumerable.Any 方法

定義

命名空間:: System.Linq

組件:: System.Core.dll, System.Linq.dll

組件:: netstandard.dll, System.Linq.dll

組件:: System.Linq.dll

組件:: System.Core.dll

組件:: netstandard.dll

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

判斷序列中任一元素是否存在或是否滿足某條件。

多載

名稱	Description
Any<TSource>(IEnumerable<TSource>)	判斷序列是否包含任何專案。
Any<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)	判斷序列的任何專案是否符合條件。

Any<TSource>(IEnumerable<TSource>)

來源:: AnyAll.cs

來源:: AnyAll.cs

來源:: AnyAll.cs

來源:: AnyAll.cs

來源:: AnyAll.cs

判斷序列是否包含任何專案。

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

類型參數

TSource

元素 source的類型。

參數

source: IEnumerable<TSource>

IEnumerable<T>檢查是否有空。

傳回

Boolean

如果來源序列包含任何專案，true;否則，false。

例外狀況

ArgumentNullException

source 是 null。

範例

下列程式代碼範例示範如何使用 Any 來判斷序列是否包含任何專案。

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 ", "")
Console.WriteLine($"The list is {text}empty.")

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

Any<TSource>(IEnumerable<TSource>) 方法傳回的布爾值通常用於 where 子句的述詞（Visual Basic 中的Where 子句）或直接呼叫 Where<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>) 方法。下列範例示範如何使用 Any 方法。

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

備註

Note

此方法不會回傳集合中的任何單一元素。相反地，它決定集合是否包含任何元素。

一旦能確定結果，該 source 列舉即停止。

在Visual Basic查詢表達式語法中，Aggregate Into Any()子句可轉譯為Any的呼叫。

另請參閱

適用於

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

來源:: AnyAll.cs

來源:: AnyAll.cs

來源:: AnyAll.cs

來源:: AnyAll.cs

來源:: AnyAll.cs

判斷序列的任何專案是否符合條件。

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

類型參數

TSource

元素 source的類型。

參數

source: IEnumerable<TSource>

一個 IEnumerable<T> 要將謂詞套用於其元素的元素。

predicate: Func<TSource,Boolean>

一個用來測試每個元素條件的函數。

傳回

Boolean

true如果來源序列不是空的，且至少有一個元素在指定的謂詞中通過測試;否則，。 false

例外狀況

ArgumentNullException

source 或 predicate 為 null。

範例

下列程式代碼範例示範如何使用 Any 來判斷序列中的任何專案是否符合條件。

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);

    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")
    Console.WriteLine($"There {text} unvaccinated animals over age 1.")
End Sub

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

備註

Note

此方法不會回傳集合中的任何單一元素。相反地，它判斷集合中的任何元素是否滿足某個條件。

一旦能確定結果，該 source 列舉即停止。

在Visual Basic查詢表達式語法中，Aggregate Into Any()子句可轉譯為Any的呼叫。

另請參閱

彙總子句（Visual Basic）

適用於

意見反應

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