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 false
。true
if the source sequence contains any elements; otherwise, false
.
例外狀況
source
為 null
。source
is null
.
範例
下列程式碼範例示範如何使用 Any 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 ", "")
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 where
Visual Basic) 中子句 (子句的述詞, Where
或直接呼叫方法的述詞 Where<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>) 。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. 下列範例將示範這種方法的用法 Any
。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中的任何一個元素。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.
source
一旦可以判斷結果,就會停止的列舉。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, Aggregate Into Any()
子句會轉譯為的調用 Any 。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>)
- Aggregate 子句 (Visual Basic)Aggregate Clause (Visual Basic)
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。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.
傳回
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
。true
if the source sequence is not empty and at least one of its elements passes the test in the specified predicate; otherwise, false
.
例外狀況
source
或 predicate
為 null
。source
or predicate
is null
.
範例
下列程式碼範例示範如何使用 Any 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")
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中的任何一個元素。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.
source
一旦可以判斷結果,就會停止的列舉。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, Aggregate Into Any()
子句會轉譯為的調用 Any 。In Visual Basic query expression syntax, an Aggregate Into Any()
clause translates to an invocation of Any.