Enumerable.Any 方法

定義

判斷序列的任何項目是否符合條件。

多載

Any<TSource>(IEnumerable<TSource>)

判斷序列是否包含任何項目。

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

判斷序列的任何項目是否符合條件。

Any<TSource>(IEnumerable<TSource>)

判斷序列是否包含任何項目。

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。

參數

source
IEnumerable<TSource>

要檢查是否為空白的 IEnumerable<T>

傳回

Boolean

如果來源序列包含任何項目,則為 true,否則為 false

例外狀況

sourcenull

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.

方法傳回的布林值 Any<TSource>(IEnumerable<TSource>) 通常用於 子句的述詞 (子句Visual Basic) Where 或直接呼叫 Where<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>) where 方法。 下列範例示範這個 方法的使用 Any 方式。

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專案。 相反地,它會判斷集合是否包含任何專案。

只要判斷結果,就會停止 列舉 source

在Visual Basic查詢運算式語法中, Aggregate Into Any() 子句會轉譯為 的 Any 調用。

另請參閱

適用於

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

判斷序列的任何項目是否符合條件。

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

source 項目的類型。

參數

source
IEnumerable<TSource>

其項目要套用述詞的 IEnumerable<T>

predicate
Func<TSource,Boolean>

用來測試每個項目是否符合條件的函式。

傳回

Boolean

若來源序列不是空的且其至少有一個元素通過指定述詞中的測試,則為 true;否則為 false

例外狀況

sourcepredicatenull

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 == 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")
    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

注意

這個方法不會傳回集合的任何一個專案。 相反地,它會判斷集合的任何專案是否符合條件。

只要判斷結果,就會停止 列舉 source

在Visual Basic查詢運算式語法中, Aggregate Into Any() 子句會轉譯為 的 Any 調用。

另請參閱

適用於