Enumerable.Any 方法

定義

判斷序列的任何項目是否符合條件。Determines whether any element of a sequence exists or satisfies a condition.

多載

Any<TSource>(IEnumerable<TSource>)

判斷序列是否包含任何項目。Determines whether a sequence contains any elements.

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

判斷序列的任何項目是否符合條件。Determines whether any element of a sequence satisfies a condition.

Any<TSource>(IEnumerable<TSource>)

判斷序列是否包含任何項目。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

類型參數

TSource

source 項目的類型。The type of the elements of source.

參數

source
IEnumerable<TSource>

要檢查是否為空白的 IEnumerable<T>The IEnumerable<T> to check for emptiness.

傳回

如果來源序列包含任何項目,則為 true,否則為 falsetrue if the source sequence contains any elements; otherwise, false.

例外狀況

sourcenullsource is null.

範例

下列程式碼範例示範如何使用 Any 來判斷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.

@No__t-0 方法傳回的布林值通常用於 @no__t 1 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。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. 下列範例示範如何使用 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

備註

注意

這個方法不會傳回集合的任何一個元素。This method does not return any one element of a collection. 相反地,它會判斷集合是否包含任何元素。Instead, it determines whether the collection contains any elements.

一旦可以判斷結果,source 的列舉就會停止。The enumeration of source is stopped as soon as the result can be determined.

在 Visual Basic 查詢運算式語法中,@no__t 0 子句會轉譯為 Any 的調用。In Visual Basic query expression syntax, an Aggregate Into Any() clause translates to an invocation of Any.

另請參閱

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

判斷序列的任何項目是否符合條件。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

類型參數

TSource

source 項目的類型。The type of the elements of source.

參數

source
IEnumerable<TSource>

其項目要套用述詞的 IEnumerable<T>An IEnumerable<T> whose elements to apply the predicate to.

predicate
Func<TSource,Boolean>

用來測試每個項目是否符合條件的函式。A function to test each element for a condition.

傳回

如果來源序列中的任何項目通過以指定之述詞進行的測試,則為 true,否則為 falsetrue if any elements in the source sequence pass the test in the specified predicate; otherwise, false.

例外狀況

sourcepredicatenullsource or predicate is null.

範例

下列程式碼範例示範如何使用 Any 來判斷序列中的任何元素是否符合條件。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.

備註

注意

這個方法不會傳回集合的任何一個元素。This method does not return any one element of a collection. 相反地,它會判斷集合的任何元素是否符合條件。Instead, it determines whether any elements of a collection satisfy a condition.

一旦可以判斷結果,source 的列舉就會停止。The enumeration of source is stopped as soon as the result can be determined.

在 Visual Basic 查詢運算式語法中,@no__t 0 子句會轉譯為 Any 的調用。In Visual Basic query expression syntax, an Aggregate Into Any() clause translates to an invocation of Any.

另請參閱

適用於