Enumerable.Union Metoda

Definice

Vytvoří sjednocení dvou sekvencí.Produces the set union of two sequences.

Přetížení

Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)

Vytvoří sjednocení dvou sekvencí pomocí výchozí porovnávače rovnosti.Produces the set union of two sequences by using the default equality comparer.

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

Vytvoří sjednocení ze dvou sekvencí pomocí zadaného typu IEqualityComparer<T> .Produces the set union of two sequences by using a specified IEqualityComparer<T>.

Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)

Vytvoří sjednocení dvou sekvencí pomocí výchozí porovnávače rovnosti.Produces the set union of two sequences by using the default equality comparer.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static System::Collections::Generic::IEnumerable<TSource> ^ Union(System::Collections::Generic::IEnumerable<TSource> ^ first, System::Collections::Generic::IEnumerable<TSource> ^ second);
public static System.Collections.Generic.IEnumerable<TSource> Union<TSource> (this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TSource> second);
static member Union : seq<'Source> * seq<'Source> -> seq<'Source>
<Extension()>
Public Function Union(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>, Jejíž odlišné prvky tvoří první sadu pro sjednocení.An IEnumerable<T> whose distinct elements form the first set for the union.

second
IEnumerable<TSource>

IEnumerable<T>Jejichž odlišné prvky tvoří druhou sadu pro sjednocení.An IEnumerable<T> whose distinct elements form the second set for the union.

Návraty

IEnumerable<TSource>

Objekt IEnumerable<T> , který obsahuje prvky z obou vstupních sekvencí s výjimkou duplicit.An IEnumerable<T> that contains the elements from both input sequences, excluding duplicates.

Výjimky

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

Příklady

Následující příklad kódu ukazuje, jak použít Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) k získání sjednocení dvou sekvencí celých čísel.The following code example demonstrates how to use Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) to obtain the union of two sequences of integers.

int[] ints1 = { 5, 3, 9, 7, 5, 9, 3, 7 };
int[] ints2 = { 8, 3, 6, 4, 4, 9, 1, 0 };

IEnumerable<int> union = ints1.Union(ints2);

foreach (int num in union)
{
    Console.Write("{0} ", num);
}

/*
 This code produces the following output:

 5 3 9 7 8 6 4 1 0
*/
' Create two arrays of integer values.
Dim ints1() As Integer = {5, 3, 9, 7, 5, 9, 3, 7}
Dim ints2() As Integer = {8, 3, 6, 4, 4, 9, 1, 0}

' Get the set union of the two arrays.
Dim union As IEnumerable(Of Integer) = ints1.Union(ints2)

' Display the resulting set's values.
Dim output As New System.Text.StringBuilder
For Each num As Integer In union
    output.AppendLine(num & " ")
Next
Console.WriteLine(output.ToString())

' This code produces the following output:
'
' 5 
' 3 
' 9 
' 7 
' 8 
' 6 
' 4 
' 1 
' 0 

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 Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) metodě, jak je znázorněno v následujícím příkladu:After you implement this interface, you can use sequences of ProductA objects in the Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) 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 both arrays
//excluding duplicates.

IEnumerable<ProductA> union =
  store1.Union(store2);

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

/*
    This code produces the following output:

    apple 9
    orange 4
    lemon 12
*/
' Get the products from the both arrays
' excluding duplicates.

Dim union = store1.Union(store2)

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

' This code produces the following output:
'
' apple 9
' orange 4
' lemon 12
' 

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.

Tato metoda vyloučí duplicity ze sady vrácených hodnot.This method excludes duplicates from the return set. Jedná se o jiné chování jako Concat metoda, která vrátí všechny prvky ve vstupních sekvencích včetně duplicitních.This is different behavior to the Concat method, which returns all the elements in the input sequences including duplicates.

Výchozí porovnávání rovnosti se Default používá k porovnání hodnot typů, které implementují IEqualityComparer<T> Obecné rozhraní.The default equality comparer, Default, is used to compare values of the types that implement the IEqualityComparer<T> generic interface. Chcete-li porovnat vlastní datový typ, je nutné implementovat toto rozhraní a zadat vlastní GetHashCode a Equals metody pro daný typ.To compare a custom data type, you need to implement this interface and provide your own GetHashCode and Equals methods for the type.

Když je objekt vrácený touto metodou vyhodnocen, Union vytvoří výčet first a second v tomto pořadí a vrátí každý prvek, který již nebyl získán.When the object returned by this method is enumerated, Union enumerates first and second in that order and yields each element that has not already been yielded.

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

Vytvoří sjednocení ze dvou sekvencí pomocí zadaného typu IEqualityComparer<T> .Produces the set union of two sequences by using a specified IEqualityComparer<T>.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static System::Collections::Generic::IEnumerable<TSource> ^ Union(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> Union<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> Union<TSource> (this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TSource> second, System.Collections.Generic.IEqualityComparer<TSource>? comparer);
static member Union : seq<'Source> * seq<'Source> * System.Collections.Generic.IEqualityComparer<'Source> -> seq<'Source>
<Extension()>
Public Function Union(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>, Jejíž odlišné prvky tvoří první sadu pro sjednocení.An IEnumerable<T> whose distinct elements form the first set for the union.

second
IEnumerable<TSource>

IEnumerable<T>Jejichž odlišné prvky tvoří druhou sadu pro sjednocení.An IEnumerable<T> whose distinct elements form the second set for the union.

comparer
IEqualityComparer<TSource>

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

Návraty

IEnumerable<TSource>

Objekt IEnumerable<T> , který obsahuje prvky z obou vstupních sekvencí s výjimkou duplicit.An IEnumerable<T> that contains the elements from both input sequences, excluding duplicates.

Výjimky

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

Příklady

Následující příklad ukazuje, jak implementovat porovnávání rovnosti, které lze použít v Union metodě.The following example shows how to implement an equality comparer that can be used in the Union 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 Union metodě, jak je znázorněno v následujícím příkladu:After you implement this comparer, you can use sequences of Product objects in the Union 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 both arrays
//excluding duplicates.

IEnumerable<Product> union =
  store1.Union(store2, new ProductComparer());

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

/*
    This code produces the following output:

    apple 9
    orange 4
    lemon 12
*/
' Get the products from the both arrays
' excluding duplicates.

Dim union = store1.Union(store2, New ProductComparer())

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

' This code produces the following output:
'
' apple 9
' orange 4
' lemon 12
' 

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.

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.

Když je objekt vrácený touto metodou vyhodnocen, Union vytvoří výčet first a second v tomto pořadí a vrátí každý prvek, který již nebyl získán.When the object returned by this method is enumerated, Union enumerates first and second in that order and yields each element that has not already been yielded.

ConcatMetoda se liší od metody, Union protože Concat Metoda vrátí všechny prvky ve vstupních sekvencích včetně duplicitních hodnot, zatímco Union vrátí pouze jedinečné hodnoty.The Concat method differs from the Union method because the Concat method returns all the elements in the input sequences including duplicates, whereas Union returns only unique values.

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