Enumerable.Count 메서드

정의

시퀀스의 요소 수를 반환합니다.Returns the number of elements in a sequence.

오버로드

Count<TSource>(IEnumerable<TSource>)

시퀀스의 요소 수를 반환합니다.Returns the number of elements in a sequence.

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

특정 조건에 맞는 지정된 된 시퀀스의 요소 수를 나타내는 숫자를 반환 합니다.Returns a number that represents how many elements in the specified sequence satisfy a condition.

Count<TSource>(IEnumerable<TSource>)

시퀀스의 요소 수를 반환합니다.Returns the number of elements in a sequence.

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

형식 매개 변수

TSource

source 요소의 형식입니다.The type of the elements of source.

매개 변수

source
IEnumerable<TSource>

개수를 셀 요소가 들어 있는 시퀀스입니다.A sequence that contains elements to be counted.

반환

Int32

입력 시퀀스의 요소 수입니다.The number of elements in the input sequence.

예외

sourcenull입니다.source is null.

source의 요소 수가 MaxValue보다 큰 경우The number of elements in source is larger than MaxValue.

예제

다음 코드 예제에서는 Count<TSource>(IEnumerable<TSource>)를 사용 하 여 배열의 요소 수를 계산 하는 방법을 보여 줍니다.The following code example demonstrates how to use Count<TSource>(IEnumerable<TSource>) to count the elements in an array.

string[] fruits = { "apple", "banana", "mango", "orange", "passionfruit", "grape" };

try
{
    int numberOfFruits = fruits.Count();
    Console.WriteLine(
        "There are {0} fruits in the collection.",
        numberOfFruits);
}
catch (OverflowException)
{
    Console.WriteLine("The count is too large to store as an Int32.");
    Console.WriteLine("Try using the LongCount() method instead.");
}

// This code produces the following output:
//
// There are 6 fruits in the collection.
' Create an array of strings.
Dim fruits() As String = {"apple", "banana", "mango", "orange", "passionfruit", "grape"}

Try
    ' Count the number of items in the array.
    Dim numberOfFruits As Integer = fruits.Count()
    ' Display the output.
    Console.WriteLine($"There are {numberOfFruits} fruits in the collection.")
Catch e As OverflowException
    Console.WriteLine("The count is too large to store as an Int32. Try using LongCount() instead.")
End Try

' This code produces the following output:
'
' There are 6 fruits in the collection.

설명

source 형식이 ICollection<T>를 구현 하는 경우 해당 구현은 요소 수를 가져오는 데 사용 됩니다.If the type of source implements ICollection<T>, that implementation is used to obtain the count of elements. 그렇지 않은 경우이 메서드는 수를 결정합니다.Otherwise, this method determines the count.

LongCount 메서드를 사용 하 여 결과를 MaxValue보다 크게 허용할 수 있습니다.Use the LongCount method when you expect and want to allow the result to be greater than MaxValue.

Visual Basic 쿼리 식 구문에서 Aggregate Into Count() 절은 Count호출로 변환 됩니다.In Visual Basic query expression syntax, an Aggregate Into Count() clause translates to an invocation of Count.

추가 정보

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

특정 조건에 맞는 지정된 된 시퀀스의 요소 수를 나타내는 숫자를 반환 합니다.Returns a number that represents how many elements in the specified sequence satisfy a condition.

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

형식 매개 변수

TSource

source 요소의 형식입니다.The type of the elements of source.

매개 변수

source
IEnumerable<TSource>

테스트 하 고 계산 요소가 있는 시퀀스입니다.A sequence that contains elements to be tested and counted.

predicate
Func<TSource,Boolean>

각 요소를 조건에 대해 테스트하는 함수입니다.A function to test each element for a condition.

반환

Int32

시퀀스에서 조건자 함수의 조건에 맞는 요소 수를 나타내는 숫자입니다.A number that represents how many elements in the sequence satisfy the condition in the predicate function.

예외

source 또는 predicatenull인 경우source or predicate is null.

source의 요소 수가 MaxValue보다 큰 경우The number of elements in source is larger than MaxValue.

예제

다음 코드 예제에서는 Count<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)를 사용 하 여 조건에 맞는 배열의 요소를 계산 하는 방법을 보여 줍니다.The following code example demonstrates how to use Count<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>) to count the elements in an array that satisfy a condition.

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

public static void CountEx2()
{
    Pet[] pets = { new Pet { Name="Barley", Vaccinated=true },
                   new Pet { Name="Boots", Vaccinated=false },
                   new Pet { Name="Whiskers", Vaccinated=false } };

    try
    {
        int numberUnvaccinated = pets.Count(p => p.Vaccinated == false);
        Console.WriteLine("There are {0} unvaccinated animals.", numberUnvaccinated);
    }
    catch (OverflowException)
    {
        Console.WriteLine("The count is too large to store as an Int32.");
        Console.WriteLine("Try using the LongCount() method instead.");
    }
}

// This code produces the following output:
//
// There are 2 unvaccinated animals.
Structure Pet
    Public Name As String
    Public Vaccinated As Boolean
End Structure

Public Shared Sub CountEx2()
    ' Create an array of Pet objects.
    Dim pets() As Pet = {New Pet With {.Name = "Barley", .Vaccinated = True},
                 New Pet With {.Name = "Boots", .Vaccinated = False},
                 New Pet With {.Name = "Whiskers", .Vaccinated = False}}

    Try
        ' Count the number of Pets in the array where the Vaccinated property is False.
        Dim numberUnvaccinated As Integer =
    pets.Count(Function(p) p.Vaccinated = False)
        ' Display the output.
        Console.WriteLine($"There are {numberUnvaccinated} unvaccinated animals.")
    Catch e As OverflowException
        Console.WriteLine("The count is too large to store as an Int32. Try using LongCount() instead.")
    End Try

End Sub

' This code produces the following output:
'
' There are 2 unvaccinated animals.

설명

source 형식이 ICollection<T>를 구현 하는 경우 해당 구현은 요소 수를 가져오는 데 사용 됩니다.If the type of source implements ICollection<T>, that implementation is used to obtain the count of elements. 그렇지 않은 경우이 메서드는 수를 결정합니다.Otherwise, this method determines the count.

LongCount 메서드를 사용 하 여 결과를 MaxValue보다 크게 허용 하는 것이 좋습니다.You should use the LongCount method when you expect and want to allow the result to be greater than MaxValue.

Visual Basic 쿼리 식 구문에서 Aggregate Into Count() 절은 Count호출로 변환 됩니다.In Visual Basic query expression syntax, an Aggregate Into Count() clause translates to an invocation of Count.

추가 정보

적용 대상