Enumerable.SequenceEqual Metoda

Definice

Určuje, zda jsou dvě sekvence stejné v souladu s porovnávacím rovností.Determines whether two sequences are equal according to an equality comparer.

Přetížení

SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)

Určuje, zda jsou dvě sekvence stejné, porovnáním prvků s použitím výchozí porovnávače rovnosti pro svůj typ.Determines whether two sequences are equal by comparing the elements by using the default equality comparer for their type.

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

Určuje, zda se dvě sekvence rovnají porovnáním jejich prvků pomocí zadaného parametru IEqualityComparer<T> .Determines whether two sequences are equal by comparing their elements by using a specified IEqualityComparer<T>.

SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)

Určuje, zda jsou dvě sekvence stejné, porovnáním prvků s použitím výchozí porovnávače rovnosti pro svůj typ.Determines whether two sequences are equal by comparing the elements by using the default equality comparer for their type.

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

Parametry typu

TSource

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

Parametry

first
IEnumerable<TSource>

IEnumerable<T>Pro porovnání s second .An IEnumerable<T> to compare to second.

second
IEnumerable<TSource>

IEnumerable<T>Pro porovnání s první sekvencí.An IEnumerable<T> to compare to the first sequence.

Návraty

Boolean

true Pokud jsou dvě zdrojové sekvence stejné délky a jejich odpovídající prvky jsou stejné podle výchozí porovnávací metody pro jejich typ; v opačném případě false .true if the two source sequences are of equal length and their corresponding elements are equal according to the default equality comparer for their type; otherwise, false.

Výjimky

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

Příklady

Následující příklady kódu ukazují, jak použít SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) k určení, zda jsou dvě sekvence stejné.The following code examples demonstrate how to use SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) to determine whether two sequences are equal. V prvních dvou příkladech metoda určuje, zda porovnávané sekvence obsahují odkazy na stejné objekty.In the first two examples, the method determines whether the compared sequences contain references to the same objects. Ve třetím a čtvrtém příkladu metoda porovnává skutečná data objektů v rámci sekvencí.In the third and fourth examples, the method compares the actual data of the objects within the sequences.

V tomto příkladu jsou sekvence stejné.In this example the sequences are equal.

class Pet
{
    public string Name { get; set; }
    public int Age { get; set; }
}

public static void SequenceEqualEx1()
{
    Pet pet1 = new Pet { Name = "Turbo", Age = 2 };
    Pet pet2 = new Pet { Name = "Peanut", Age = 8 };

    // Create two lists of pets.
    List<Pet> pets1 = new List<Pet> { pet1, pet2 };
    List<Pet> pets2 = new List<Pet> { pet1, pet2 };

    bool equal = pets1.SequenceEqual(pets2);

    Console.WriteLine(
        "The lists {0} equal.",
        equal ? "are" : "are not");
}

/*
 This code produces the following output:

 The lists are equal.
*/
Class Pet
    Public Name As String
    Public Age As Integer
End Class

Sub SequenceEqualEx1()
    ' Create two Pet objects.
    Dim pet1 As New Pet With {.Name = "Turbo", .Age = 2}
    Dim pet2 As New Pet With {.Name = "Peanut", .Age = 8}

    ' Create two lists of pets.
    Dim pets1 As New List(Of Pet)(New Pet() {pet1, pet2})
    Dim pets2 As New List(Of Pet)(New Pet() {pet1, pet2})

    'Determine if the two lists are equal.
    Dim equal As Boolean = pets1.SequenceEqual(pets2)

    ' Display the output.
    Dim text As String = IIf(equal, "are", "are not")
    Console.WriteLine($"The lists {text} equal.")

End Sub

' This code produces the following output:
'
' The lists are equal.

Následující příklad kódu porovnává dvě sekvence, které nejsou stejné.The following code example compares two sequences that are not equal. Všimněte si, že sekvence obsahují stejná data, ale vzhledem k tomu, že objekty, které obsahují, mají různé odkazy, sekvence nejsou považovány za stejné.Note that the sequences contain identical data, but because the objects that they contain have different references, the sequences are not considered equal.

class Pet
{
    public string Name { get; set; }
    public int Age { get; set; }
}

public static void SequenceEqualEx2()
{
    Pet pet1 = new Pet() { Name = "Turbo", Age = 2 };
    Pet pet2 = new Pet() { Name = "Peanut", Age = 8 };

    // Create two lists of pets.
    List<Pet> pets1 = new List<Pet> { pet1, pet2 };
    List<Pet> pets2 =
        new List<Pet> { new Pet { Name = "Turbo", Age = 2 },
                        new Pet { Name = "Peanut", Age = 8 } };

    bool equal = pets1.SequenceEqual(pets2);

    Console.WriteLine("The lists {0} equal.", equal ? "are" : "are not");
}

/*
 This code produces the following output:

 The lists are not equal.
*/
' Create two Pet objects.
Dim pet1 As New Pet With {.Name = "Turbo", .Age = 2}
Dim pet2 As New Pet With {.Name = "Peanut", .Age = 8}

' Create two lists of pets.
Dim pets1 As New List(Of Pet)()
pets1.Add(pet1)
pets1.Add(pet2)

Dim pets2 As New List(Of Pet)()
pets2.Add(New Pet With {.Name = "Turbo", .Age = 2})
pets2.Add(New Pet With {.Name = "Peanut", .Age = 8})

' Determine if the two lists are equal.
Dim equal As Boolean = pets1.SequenceEqual(pets2)

' Display the output.
Dim text As String = IIf(equal, "are", "are not")
Console.WriteLine($"The lists {text} equal.")

' This code produces the following output:
'
' The lists are not equal.

Chcete-li porovnat skutečná data objektů v sekvencích místo pouhého porovnání jejich odkazů, je nutné IEqualityComparer<T> ve třídě implementovat obecné rozhraní.If you want to compare the actual data of the objects in the sequences instead of just comparing their references, you have to implement the IEqualityComparer<T> generic interface in your class. Následující příklad kódu ukazuje, jak implementovat toto rozhraní v pomocné třídě a poskytnout GetHashCode a Equals metody.The following code example shows how to implement this interface in a helper class and provide 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 SequenceEqual<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 SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) method, as shown in the following example:


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

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

bool equalAB = storeA.SequenceEqual(storeB);

Console.WriteLine("Equal? " + equalAB);

/*
    This code produces the following output:

    Equal? True
*/
Dim storeA() As Product = 
    {New Product With {.Name = "apple", .Code = 9}, 
     New Product With {.Name = "orange", .Code = 4}}

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

Dim equalAB = storeA.SequenceEqual(storeB)

Console.WriteLine("Equal? " & equalAB)

' This code produces the following output:

' Equal? True

Poznámky

Metoda sestaví SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) dvě zdrojové sekvence paralelně a porovná odpovídající prvky pomocí výchozí porovnávače rovnosti pro TSource , Default .The SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) method enumerates the two source sequences in parallel and compares corresponding elements by using the default equality comparer for TSource, Default.

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.

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

Určuje, zda se dvě sekvence rovnají porovnáním jejich prvků pomocí zadaného parametru IEqualityComparer<T> .Determines whether two sequences are equal by comparing their elements by using a specified IEqualityComparer<T>.

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

Parametry typu

TSource

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

Parametry

first
IEnumerable<TSource>

IEnumerable<T>Pro porovnání s second .An IEnumerable<T> to compare to second.

second
IEnumerable<TSource>

IEnumerable<T>Pro porovnání s první sekvencí.An IEnumerable<T> to compare to the first sequence.

comparer
IEqualityComparer<TSource>

IEqualityComparer<T>Slouží k porovnání prvků.An IEqualityComparer<T> to use to compare elements.

Návraty

Boolean

true Pokud jsou dvě zdrojové sekvence stejné délky a jejich odpovídající prvky se shodují se stejným počtem comparer ; v opačném případě false .true if the two source sequences are of equal length and their corresponding elements compare equal according to comparer; otherwise, false.

Výjimky

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

Příklady

Následující příklad ukazuje, jak implementovat porovnávání rovnosti, které lze použít v SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>) metodě.The following example shows how to implement an equality comparer that can be used in the SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>) 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 SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>) metodě, jak je znázorněno v následujícím příkladu:After you implement this comparer, you can use sequences of Product objects in the SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>) method, as shown in the following example:


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

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

bool equalAB = storeA.SequenceEqual(storeB, new ProductComparer());

Console.WriteLine("Equal? " + equalAB);

/*
    This code produces the following output:

    Equal? True
*/


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

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

Dim equalAB = storeA.SequenceEqual(storeB, New ProductComparer())

Console.WriteLine("Equal? " & equalAB)

' This code produces the following output:

' Equal? True

Poznámky

SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)Metoda vytvoří paralelní výčet dvou zdrojových sekvencí a porovná odpovídající prvky pomocí zadaného IEqualityComparer<T> .The SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>) method enumerates the two source sequences in parallel and compares corresponding elements by using the specified IEqualityComparer<T>. Pokud comparer je null , použije se výchozí porovnávání rovnosti Default pro porovnání prvků.If comparer is null, the default equality comparer, Default, is used to compare elements.

Platí pro