Enumerable.Contains Method

Definition

시퀀스에 지정된 요소가 들어 있는지를 확인합니다.Determines whether a sequence contains a specified element.

Overloads

Contains<TSource>(IEnumerable<TSource>, TSource)

기본 같음 비교자를 사용하여 시퀀스에 지정된 요소가 들어 있는지 확인합니다.Determines whether a sequence contains a specified element by using the default equality comparer.

Contains<TSource>(IEnumerable<TSource>, TSource, IEqualityComparer<TSource>)

지정된 IEqualityComparer<T>를 사용하여 시퀀스에 지정된 요소가 들어 있는지 확인합니다.Determines whether a sequence contains a specified element by using a specified IEqualityComparer<T>.

Contains<TSource>(IEnumerable<TSource>, TSource)

기본 같음 비교자를 사용하여 시퀀스에 지정된 요소가 들어 있는지 확인합니다.Determines whether a sequence contains a specified element by using the default equality comparer.

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

Type Parameters

TSource

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

Parameters

source
IEnumerable<TSource>

값을 찾을 시퀀스입니다.A sequence in which to locate a value.

value
TSource

시퀀스에서 찾을 값입니다.The value to locate in the sequence.

Returns

Boolean

소스 시퀀스에 지정된 값을 갖는 요소가 들어 있으면 true이고, 그렇지 않으면 false입니다.true if the source sequence contains an element that has the specified value; otherwise, false.

Exceptions

sourcenull입니다.source is null.

Examples

다음 코드 예제에서는 Contains<TSource>(IEnumerable<TSource>, TSource)를 사용 하 여 배열에 특정 요소가 들어 있는지 여부를 확인 하는 방법을 보여 줍니다.The following code example demonstrates how to use Contains<TSource>(IEnumerable<TSource>, TSource) to determine whether an array contains a specific element.

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

string fruit = "mango";

bool hasMango = fruits.Contains(fruit);

Console.WriteLine(
    "The array {0} contain '{1}'.",
    hasMango ? "does" : "does not",
    fruit);

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

' This is the string to search the array for.
Dim fruit As String = "mango"

' Determine if the array contains the specified string.
Dim hasMango As Boolean = fruits.Contains(fruit)

Dim text As String = IIf(hasMango, "does", "does not")

' Display the output.
Console.WriteLine($"The array {text} contain {fruit}")

' This code produces the following output:
'
' The array does contain mango

Remarks

source 형식이 ICollection<T>를 구현 하는 경우 해당 구현의 Contains 메서드를 호출 하 여 결과를 얻습니다.If the type of source implements ICollection<T>, the Contains method in that implementation is invoked to obtain the result. 그렇지 않으면이 메서드는 source에 지정 된 요소가 포함 되어 있는지 여부를 확인 합니다.Otherwise, this method determines whether source contains the specified element.

열거형에는 일치 하는 요소가 발견 되는 즉시 종료 됩니다.Enumeration is terminated as soon as a matching element is found.

기본 같음 비교자 인 Default를 사용 하 여 요소를 지정 된 값과 비교 합니다.Elements are compared to the specified value by using the default equality comparer, Default.

Contains<TSource>(IEnumerable<TSource>, TSource, IEqualityComparer<TSource>)

지정된 IEqualityComparer<T>를 사용하여 시퀀스에 지정된 요소가 들어 있는지 확인합니다.Determines whether a sequence contains a specified element by using a specified IEqualityComparer<T>.

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

Type Parameters

TSource

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

Parameters

source
IEnumerable<TSource>

값을 찾을 시퀀스입니다.A sequence in which to locate a value.

value
TSource

시퀀스에서 찾을 값입니다.The value to locate in the sequence.

comparer
IEqualityComparer<TSource>

값을 비교할 같음 비교자입니다.An equality comparer to compare values.

Returns

Boolean

소스 시퀀스에 지정된 값을 갖는 요소가 들어 있으면 true이고, 그렇지 않으면 false입니다.true if the source sequence contains an element that has the specified value; otherwise, false.

Exceptions

sourcenull입니다.source is null.

Examples

다음 예제에서는 Contains 메서드에서 사용할 수 있는 같음 비교자를 구현 하는 방법을 보여 줍니다.The following example shows how to implement an equality comparer that can be used in the Contains method.

public class Product
{
    public string Name { get; set; }
    public int Code { get; set; }
}

// Custom comparer for the Product class
class ProductComparer : IEqualityComparer<Product>
{
    // Products are equal if their names and product numbers are equal.
    public bool Equals(Product x, Product y)
    {

        //Check whether the compared objects reference the same data.
        if (Object.ReferenceEquals(x, y)) return true;

        //Check whether any of the compared objects is null.
        if (Object.ReferenceEquals(x, null) || Object.ReferenceEquals(y, null))
            return false;

        //Check whether the products' properties are equal.
        return x.Code == y.Code && x.Name == y.Name;
    }

    // If Equals() returns true for a pair of objects
    // then GetHashCode() must return the same value for these objects.

    public int GetHashCode(Product product)
    {
        //Check whether the object is null
        if (Object.ReferenceEquals(product, null)) return 0;

        //Get hash code for the Name field if it is not null.
        int hashProductName = product.Name == null ? 0 : product.Name.GetHashCode();

        //Get hash code for the Code field.
        int hashProductCode = product.Code.GetHashCode();

        //Calculate the hash code for the product.
        return hashProductName ^ hashProductCode;
    }
}
Public Class Product
    Public Property Name As String
    Public Property Code As Integer
End Class

' Custom comparer for the Product class
Public Class ProductComparer
    Implements IEqualityComparer(Of Product)

    Public Function Equals1(
        ByVal x As Product, 
        ByVal y As Product
        ) As Boolean Implements IEqualityComparer(Of Product).Equals

        ' Check whether the compared objects reference the same data.
        If x Is y Then Return True

        'Check whether any of the compared objects is null.
        If x Is Nothing OrElse y Is Nothing Then Return False

        ' Check whether the products' properties are equal.
        Return (x.Code = y.Code) AndAlso (x.Name = y.Name)
    End Function

    Public Function GetHashCode1(
        ByVal product As Product
        ) As Integer Implements IEqualityComparer(Of Product).GetHashCode

        ' Check whether the object is null.
        If product Is Nothing Then Return 0

        ' Get hash code for the Name field if it is not null.
        Dim hashProductName = 
            If(product.Name Is Nothing, 0, product.Name.GetHashCode())

        ' Get hash code for the Code field.
        Dim hashProductCode = product.Code.GetHashCode()

        ' Calculate the hash code for the product.
        Return hashProductName Xor hashProductCode
    End Function
End Class

이 비교자를 구현한 후에는 다음 예제와 같이 Contains 메서드에서 Product 개체의 시퀀스를 사용할 수 있습니다.After you implement this comparer, you can use a sequence of Product objects in the Contains method, as shown in the following example:


Product[] fruits = { new Product { Name = "apple", Code = 9 },
                       new Product { Name = "orange", Code = 4 },
                       new Product { Name = "lemon", Code = 12 } };

Product apple = new Product { Name = "apple", Code = 9 };
Product kiwi = new Product {Name = "kiwi", Code = 8 };

ProductComparer prodc = new ProductComparer();

bool hasApple = fruits.Contains(apple, prodc);
bool hasKiwi = fruits.Contains(kiwi, prodc);

Console.WriteLine("Apple? " + hasApple);
Console.WriteLine("Kiwi? " + hasKiwi);

/*
    This code produces the following output:

    Apple? True
    Kiwi? False
*/


Dim fruits() As Product = 
   {New Product With {.Name = "apple", .Code = 9}, 
    New Product With {.Name = "orange", .Code = 4}, 
    New Product With {.Name = "lemon", .Code = 12}}

Dim apple = New Product With {.Name = "apple", .Code = 9}
Dim kiwi = New Product With {.Name = "kiwi", .Code = 8}

Dim prodc As New ProductComparer()

Dim hasApple = fruits.Contains(apple, prodc)
Dim hasKiwi = fruits.Contains(kiwi, prodc)

Console.WriteLine("Apple? " & hasApple)
Console.WriteLine("Kiwi? " & hasKiwi)


' This code produces the following output:
'
' Apple? True
' Kiwi? False

Remarks

열거형에는 일치 하는 요소가 발견 되는 즉시 종료 됩니다.Enumeration is terminated as soon as a matching element is found.

comparer null되는 경우 기본 같음 비교자 인 Default를 사용 하 여 요소를 지정 된 값과 비교 합니다.If comparer is null, the default equality comparer, Default, is used to compare elements to the specified value.

Applies to