Enumerable.SequenceEqual Método

Source:

SequenceEqual.cs

Source:

SequenceEqual.cs

Source:

SequenceEqual.cs

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

Parámetros de tipo

Parámetros

Devoluciones

true si las dos secuencias de origen tienen la misma longitud y sus elementos correspondientes son iguales según el comparador de igualdad predeterminado para su tipo; de lo contrario, false.

Excepciones

Ejemplos

En los ejemplos de código siguientes se muestra cómo usar SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) para determinar si dos secuencias son iguales. En los dos primeros ejemplos, el método determina si las secuencias comparados contienen referencias a los mismos objetos. En el tercer y cuarto ejemplo, el método compara los datos reales de los objetos dentro de las secuencias.

En este ejemplo, las secuencias son iguales.

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.

En el ejemplo de código siguiente se comparan dos secuencias que no son iguales. Tenga en cuenta que las secuencias contienen datos idénticos, pero porque los objetos que contienen tienen referencias diferentes, las secuencias no se consideran iguales.

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.

Si desea comparar los datos reales de los objetos en las secuencias en lugar de simplemente comparar sus referencias, debe implementar la interfaz genérica en la IEqualityComparer<T> clase . En el ejemplo de código siguiente se muestra cómo implementar esta interfaz en una clase auxiliar y proporcionar GetHashCode métodos y Equals .

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

Después de implementar esta interfaz, puede usar secuencias de ProductA objetos en el SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) método , como se muestra en el ejemplo siguiente:

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

Comentarios

El SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) método enumera las dos secuencias de origen en paralelo y compara los elementos correspondientes mediante el comparador de igualdad predeterminado para TSource, Default.

El comparador de igualdad predeterminado, Default, se usa para comparar valores de los tipos. Para comparar un tipo de datos personalizado, debe invalidar los Equals métodos y GetHashCode y, opcionalmente, implementar la IEquatable<T> interfaz genérica en el tipo personalizado. Para obtener más información, vea la propiedad Default.

Source:

SequenceEqual.cs

Source:

SequenceEqual.cs

Source:

SequenceEqual.cs

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

Parámetros de tipo

Parámetros

Devoluciones

true si las dos secuencias de origen tienen la misma longitud y sus elementos correspondientes son iguales según comparer; de lo contrario, false.

Excepciones

Ejemplos

En el ejemplo siguiente se muestra cómo implementar un comparador de igualdad que se puede usar en el SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>) método .

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

Después de implementar este comparador, puede usar secuencias de Product objetos en el SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>) método , como se muestra en el ejemplo siguiente:

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

Comentarios

El SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>) método enumera las dos secuencias de origen en paralelo y compara los elementos correspondientes mediante el especificado IEqualityComparer<T>. Si comparer es null, el comparador de igualdad predeterminado, Default, se usa para comparar elementos.