Enumerable.Intersect Méthode

Définition

Produit l'intersection de deux séquences.Produces the set intersection of two sequences.

Surcharges

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

Produit l'intersection entre deux séquences à l'aide du IEqualityComparer<T> spécifié pour comparer les valeurs.Produces the set intersection of two sequences by using the specified IEqualityComparer<T> to compare values.

Intersect<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)

Produit l'intersection de deux séquences à l'aide du comparateur d'égalité par défaut pour comparer les valeurs.Produces the set intersection of two sequences by using the default equality comparer to compare values.

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

Produit l'intersection entre deux séquences à l'aide du IEqualityComparer<T> spécifié pour comparer les valeurs.Produces the set intersection of two sequences by using the specified IEqualityComparer<T> to compare values.

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

Paramètres de type

TSource

Type des éléments des séquences d'entrée.The type of the elements of the input sequences.

Paramètres

first
IEnumerable<TSource>

IEnumerable<T> dont les éléments distincts qui apparaissent également dans second seront retournés.An IEnumerable<T> whose distinct elements that also appear in second will be returned.

second
IEnumerable<TSource>

IEnumerable<T> dont les éléments distincts qui apparaissent également dans la première séquence seront retournés.An IEnumerable<T> whose distinct elements that also appear in the first sequence will be returned.

comparer
IEqualityComparer<TSource>

IEqualityComparer<T> pour comparer les valeurs.An IEqualityComparer<T> to compare values.

Retours

IEnumerable<TSource>

Séquence qui contient les éléments constituant l'intersection de les deux séquences.A sequence that contains the elements that form the set intersection of two sequences.

Exceptions

first ou second est null.first or second is null.

Exemples

L’exemple suivant montre comment implémenter un comparateur d’égalité qui peut être utilisé dans la Intersect méthode.The following example shows how to implement an equality comparer that can be used in the Intersect 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

Après avoir implémenté ce comparateur, vous pouvez utiliser des séquences d' Product objets dans la Intersect méthode, comme indiqué dans l’exemple suivant :After you implement this comparer, you can use sequences of Product objects in the Intersect method, as shown in the following example:

Product[] store1 = { new Product { Name = "apple", Code = 9 },
                       new Product { Name = "orange", Code = 4 } };

Product[] store2 = { new Product { Name = "apple", Code = 9 },
                       new Product { Name = "lemon", Code = 12 } };
Dim store1() As Product = 
    {New Product With {.Name = "apple", .Code = 9}, 
     New Product With {.Name = "orange", .Code = 4}}

Dim store2() As Product = 
    {New Product With {.Name = "apple", .Code = 9}, 
     New Product With {.Name = "lemon", .Code = 12}}
// Get the products from the first array
// that have duplicates in the second array.

IEnumerable<Product> duplicates =
    store1.Intersect(store2, new ProductComparer());

foreach (var product in duplicates)
    Console.WriteLine(product.Name + " " + product.Code);

/*
    This code produces the following output:
    apple 9
*/
' Get the products from the first array 
' that have duplicates in the second array.

Dim duplicates = store1.Intersect(store2, New ProductComparer())

For Each product In duplicates
    Console.WriteLine(product.Name & " " & product.Code)
Next

' This code produces the following output:
'
' apple 9
' 

Remarques

Cette méthode est implémentée à l’aide de l’exécution différée.This method is implemented by using deferred execution. La valeur de retour immédiate est un objet qui stocke toutes les informations requises pour effectuer l’action.The immediate return value is an object that stores all the information that is required to perform the action. La requête représentée par cette méthode n’est pas exécutée tant que l’objet n’est pas énuméré soit en appelant sa GetEnumerator méthode directement, soit en utilisant foreach en Visual C# ou For Each dans Visual Basic.The query represented by this method is not executed until the object is enumerated either by calling its GetEnumerator method directly or by using foreach in Visual C# or For Each in Visual Basic.

L’intersection de deux jeux A et B est définie comme étant l’ensemble qui contient tous les éléments d’un qui apparaissent également dans B, mais pas d’autres éléments.The intersection of two sets A and B is defined as the set that contains all the elements of A that also appear in B, but no other elements.

Lorsque l’objet retourné par cette méthode est énuméré, Intersect produit des éléments distincts qui se produisent dans les deux séquences dans l’ordre dans lequel ils apparaissent dans first .When the object returned by this method is enumerated, Intersect yields distinct elements occurring in both sequences in the order in which they appear in first.

Si comparer est null , le comparateur d’égalité par défaut, Default , est utilisé pour comparer les valeurs.If comparer is null, the default equality comparer, Default, is used to compare values.

S’applique à

Intersect<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)

Produit l'intersection de deux séquences à l'aide du comparateur d'égalité par défaut pour comparer les valeurs.Produces the set intersection of two sequences by using the default equality comparer to compare values.

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

Paramètres de type

TSource

Type des éléments des séquences d'entrée.The type of the elements of the input sequences.

Paramètres

first
IEnumerable<TSource>

IEnumerable<T> dont les éléments distincts qui apparaissent également dans second seront retournés.An IEnumerable<T> whose distinct elements that also appear in second will be returned.

second
IEnumerable<TSource>

IEnumerable<T> dont les éléments distincts qui apparaissent également dans la première séquence seront retournés.An IEnumerable<T> whose distinct elements that also appear in the first sequence will be returned.

Retours

IEnumerable<TSource>

Séquence qui contient les éléments constituant l'intersection de les deux séquences.A sequence that contains the elements that form the set intersection of two sequences.

Exceptions

first ou second est null.first or second is null.

Exemples

L’exemple de code suivant montre comment utiliser Intersect<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) pour retourner les éléments qui apparaissent dans chacune des deux séquences d’entiers.The following code example demonstrates how to use Intersect<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) to return the elements that appear in each of two sequences of integers.

int[] id1 = { 44, 26, 92, 30, 71, 38 };
int[] id2 = { 39, 59, 83, 47, 26, 4, 30 };

IEnumerable<int> both = id1.Intersect(id2);

foreach (int id in both)
    Console.WriteLine(id);

/*
 This code produces the following output:

 26
 30
*/
' Create two integer arrays.
Dim id1() As Integer = {44, 26, 92, 30, 71, 38}
Dim id2() As Integer = {39, 59, 83, 47, 26, 4, 30}

' Find the set intersection of the two arrays.
Dim intersection As IEnumerable(Of Integer) = id1.Intersect(id2)

Dim output As New System.Text.StringBuilder
For Each id As Integer In intersection
    output.AppendLine(id)
Next

' Display the output.
Console.WriteLine(output.ToString)

' This code produces the following output:
'
' 26
' 30

Si vous souhaitez comparer des séquences d’objets de certains types de données personnalisés, vous devez implémenter l' IEquatable<T> interface générique dans une classe d’assistance.If you want to compare sequences of objects of some custom data type, you have to implement the IEquatable<T> generic interface in a helper class. L’exemple de code suivant montre comment implémenter cette interface dans un type de données personnalisé et substituer GetHashCode des Equals méthodes et.The following code example shows how to implement this interface in a custom data type and override GetHashCode and Equals methods.

public class ProductA: IEquatable<ProductA>
{
    public string Name { get; set; }
    public int Code { get; set; }

    public bool Equals(ProductA other)
    {
        if (other is null)
            return false;

        return this.Name == other.Name && this.Code == other.Code;
    }

    public override bool Equals(object obj) => Equals(obj as ProductA);
    public override int GetHashCode() => (Name, Code).GetHashCode();
}
Public Class ProductA
    Inherits IEquatable(Of ProductA)

    Public Property Name As String
    Public Property Code As Integer

    Public Function Equals(ByVal other As ProductA) As Boolean
        If other Is Nothing Then Return False
        Return Me.Name = other.Name AndAlso Me.Code = other.Code
    End Function

    Public Overrides Function Equals(ByVal obj As Object) As Boolean
        Return Equals(TryCast(obj, ProductA))
    End Function

    Public Overrides Function GetHashCode() As Integer
        Return (Name, Code).GetHashCode()
    End Function

End Class

Après avoir implémenté cette interface, vous pouvez utiliser des séquences d' ProductA objets dans la Intersect méthode, comme indiqué dans l’exemple suivant :After you implement this interface, you can use sequences of ProductA objects in the Intersect method, as shown in the following example:

ProductA[] store1 = { new ProductA { Name = "apple", Code = 9 },
                       new ProductA { Name = "orange", Code = 4 } };

ProductA[] store2 = { new ProductA { Name = "apple", Code = 9 },
                       new ProductA { Name = "lemon", Code = 12 } };
Dim store1() As ProductA = 
    {New Product With {.Name = "apple", .Code = 9}, 
     New Product With {.Name = "orange", .Code = 4}}

Dim store2() As ProductA = 
    {New Product With {.Name = "apple", .Code = 9}, 
     New Product With {.Name = "lemon", .Code = 12}}
// Get the products from the first array
// that have duplicates in the second array.

IEnumerable<ProductA> duplicates =
    store1.Intersect(store2);

foreach (var product in duplicates)
    Console.WriteLine(product.Name + " " + product.Code);

/*
    This code produces the following output:
    apple 9
*/
' Get the products from the first array 
' that have duplicates in the second array.

Dim duplicates = store1.Intersect(store2)

For Each product In duplicates
    Console.WriteLine(product.Name & " " & product.Code)
Next

' This code produces the following output:
'
' apple 9
' 

Remarques

Cette méthode est implémentée à l’aide de l’exécution différée.This method is implemented by using deferred execution. La valeur de retour immédiate est un objet qui stocke toutes les informations requises pour effectuer l’action.The immediate return value is an object that stores all the information that is required to perform the action. La requête représentée par cette méthode n’est pas exécutée tant que l’objet n’est pas énuméré soit en appelant sa GetEnumerator méthode directement, soit en utilisant foreach en Visual C# ou For Each dans Visual Basic.The query represented by this method is not executed until the object is enumerated either by calling its GetEnumerator method directly or by using foreach in Visual C# or For Each in Visual Basic.

L’intersection de deux jeux A et B est définie comme étant l’ensemble qui contient tous les éléments d’un qui apparaissent également dans B, mais pas d’autres éléments.The intersection of two sets A and B is defined as the set that contains all the elements of A that also appear in B, but no other elements.

Lorsque l’objet retourné par cette méthode est énuméré, Intersect produit des éléments distincts qui se produisent dans les deux séquences dans l’ordre dans lequel ils apparaissent dans first .When the object returned by this method is enumerated, Intersect yields distinct elements occurring in both sequences in the order in which they appear in first.

Le comparateur d’égalité par défaut, Default , est utilisé pour comparer les valeurs des types.The default equality comparer, Default, is used to compare values of the types. Pour comparer un type de données personnalisé, vous devez substituer les Equals méthodes et GetHashCode , et implémenter éventuellement l' IEquatable<T> interface générique dans le type personnalisé.To compare a custom data type, you need to override the Equals and the GetHashCode methods, and optionally implement the IEquatable<T> generic interface in the custom type. Pour plus d'informations, consultez la propriété Default.For more information, see the Default property.

S’applique à