Enumerable.Intersect Metoda

Definice

Vytvoří průnik dvou sekvencí sady.Produces the set intersection of two sequences.

Přetížení

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

Vytvoří průnik dvou sekvencí sady pomocí zadaného IEqualityComparer<T> pro porovnání hodnot.Produces the set intersection of two sequences by using the specified IEqualityComparer<T> to compare values.

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

Vytvoří průniky sady dvou sekvencí pomocí výchozí porovnávače rovnosti pro porovnání hodnot.Produces the set intersection of two sequences by using the default equality comparer to compare values.

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

Vytvoří průnik dvou sekvencí sady pomocí zadaného IEqualityComparer<T> pro porovnání hodnot.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)

Parametry typu

TSource

Typ prvků vstupních sekvencí.The type of the elements of the input sequences.

Parametry

first
IEnumerable<TSource>

IEnumerable<T>Vrátí se odlišné prvky, které se také zobrazí v části second .An IEnumerable<T> whose distinct elements that also appear in second will be returned.

second
IEnumerable<TSource>

IEnumerable<T>Vrátí se odlišné prvky, které se také zobrazí v první sekvenci.An IEnumerable<T> whose distinct elements that also appear in the first sequence will be returned.

comparer
IEqualityComparer<TSource>

IEqualityComparer<T>Pro porovnání hodnot.An IEqualityComparer<T> to compare values.

Návraty

IEnumerable<TSource>

Sekvence, která obsahuje prvky, které tvoří průnik dvou sekvencí sady.A sequence that contains the elements that form the set intersection of two sequences.

Výjimky

first nebo second je null .first or second is null.

Příklady

Následující příklad ukazuje, jak implementovat porovnávání rovnosti, které lze použít v Intersect metodě.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

Po implementaci této porovnávací metody můžete použít sekvence Product objektů v Intersect metodě, jak je znázorněno v následujícím příkladu: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
' 

Poznámky

Tato metoda je implementována pomocí odloženého provedení.This method is implemented by using deferred execution. Okamžitá návratová hodnota je objekt, který ukládá všechny informace, které jsou požadovány k provedení této akce.The immediate return value is an object that stores all the information that is required to perform the action. Dotaz reprezentovaný touto metodou není proveden, dokud se nevytvoří výčet objektu buď voláním GetEnumerator metody přímo nebo pomocí foreach jazyka Visual C# nebo For Each 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.

Průnik dvou sad a a B je definován jako sada, která obsahuje všechny prvky, které se také zobrazí v B, ale žádné jiné prvky.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.

Když je objekt vrácený touto metodou vyhodnocen, výsledkem jsou Intersect odlišné prvky, které se vyskytují v obou sekvencích v pořadí, ve kterém jsou uvedeny v 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.

Pokud comparer je null , je použita výchozí srovnávací porovnávání rovnosti Default hodnot.If comparer is null, the default equality comparer, Default, is used to compare values.

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

Vytvoří průniky sady dvou sekvencí pomocí výchozí porovnávače rovnosti pro porovnání hodnot.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)

Parametry typu

TSource

Typ prvků vstupních sekvencí.The type of the elements of the input sequences.

Parametry

first
IEnumerable<TSource>

IEnumerable<T>Vrátí se odlišné prvky, které se také zobrazí v části second .An IEnumerable<T> whose distinct elements that also appear in second will be returned.

second
IEnumerable<TSource>

IEnumerable<T>Vrátí se odlišné prvky, které se také zobrazí v první sekvenci.An IEnumerable<T> whose distinct elements that also appear in the first sequence will be returned.

Návraty

IEnumerable<TSource>

Sekvence, která obsahuje prvky, které tvoří průnik dvou sekvencí sady.A sequence that contains the elements that form the set intersection of two sequences.

Výjimky

first nebo second je null .first or second is null.

Příklady

Následující příklad kódu ukazuje, jak použít Intersect<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) k vrácení prvků, které se zobrazí v každém ze dvou sekvencí celých čísel.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

Chcete-li porovnat sekvence objektů určitého vlastního datového typu, je nutné implementovat IEquatable<T> Obecné rozhraní v pomocné třídě.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. Následující příklad kódu ukazuje, jak implementovat toto rozhraní ve vlastním datovém typu a přepsat GetHashCode a Equals metody.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

Po implementaci tohoto rozhraní můžete použít sekvence ProductA objektů v Intersect metodě, jak je znázorněno v následujícím příkladu: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
' 

Poznámky

Tato metoda je implementována pomocí odloženého provedení.This method is implemented by using deferred execution. Okamžitá návratová hodnota je objekt, který ukládá všechny informace, které jsou požadovány k provedení této akce.The immediate return value is an object that stores all the information that is required to perform the action. Dotaz reprezentovaný touto metodou není proveden, dokud se nevytvoří výčet objektu buď voláním GetEnumerator metody přímo nebo pomocí foreach jazyka Visual C# nebo For Each 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.

Průnik dvou sad a a B je definován jako sada, která obsahuje všechny prvky, které se také zobrazí v B, ale žádné jiné prvky.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.

Když je objekt vrácený touto metodou vyhodnocen, výsledkem jsou Intersect odlišné prvky, které se vyskytují v obou sekvencích v pořadí, ve kterém jsou uvedeny v 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.

Výchozí porovnávání rovnosti se Default používá k porovnání hodnot typů.The default equality comparer, Default, is used to compare values of the types. Chcete-li porovnat vlastní datový typ, je nutné přepsat Equals a metody a GetHashCode volitelně implementovat IEquatable<T> Obecné rozhraní vlastního typu.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. Další informace najdete v tématu Default vlastnost.For more information, see the Default property.

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