Enumerable.Except Enumerable.Except Enumerable.Except Enumerable.Except Method

Definición

Proporciona la diferencia de conjuntos de dos secuencias.Produces the set difference of two sequences.

Sobrecargas

Except<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) Except<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) Except<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) Except<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)

Proporciona la diferencia de conjuntos de dos secuencias utilizando el comparador de igualdad predeterminado para comparar los valores.Produces the set difference of two sequences by using the default equality comparer to compare values.

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

Proporciona la diferencia de conjuntos de dos secuencias utilizando el objeto IEqualityComparer<T> especificado para comparar los valores.Produces the set difference of two sequences by using the specified IEqualityComparer<T> to compare values.

Comentarios

La diferencia de conjunto de dos conjuntos se define como los miembros del primer conjunto que no aparecen en el segundo conjunto.The set difference of two sets is defined as the members of the first set that don't appear in the second set.

Este método devuelve los elementos de first que no aparecen en second.This method returns those elements in first that don't appear in second. No devuelve los elementos de second que no aparecen en. firstIt doesn't return those elements in second that don't appear in first. Solo se devuelven los elementos únicos.Only unique elements are returned.

Nota

Algunos de los ejemplos de C# de este artículo se ejecutan en el ejecutor de código en línea y área de juegos de Try.NET.Some of the C# examples in this article run in the Try.NET inline code runner and playground. Si está presente, haga clic en el botón Ejecutar para ejecutar un ejemplo en una ventana interactiva.When present, select the Run button to run an example in an interactive window. Una vez que se ejecuta el código, puede modificar y ejecutar el código modificado si vuelve a hacer clic en Ejecutar.Once you execute the code, you can modify it and run the modified code by selecting Run again. El código modificado se ejecuta en la ventana interactiva o, si se produce un error en la compilación, en la ventana interactiva se muestran todos los mensajes de error del compilador de C#.The modified code either runs in the interactive window or, if compilation fails, the interactive window displays all C# compiler error messages.

Except<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) Except<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) Except<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) Except<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)

Proporciona la diferencia de conjuntos de dos secuencias utilizando el comparador de igualdad predeterminado para comparar los valores.Produces the set difference 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> ^ Except(System::Collections::Generic::IEnumerable<TSource> ^ first, System::Collections::Generic::IEnumerable<TSource> ^ second);
public static System.Collections.Generic.IEnumerable<TSource> Except<TSource> (this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TSource> second);
static member Except : seq<'Source> * seq<'Source> -> seq<'Source>
<Extension()>
Public Function Except(Of TSource) (first As IEnumerable(Of TSource), second As IEnumerable(Of TSource)) As IEnumerable(Of TSource)

Parámetros de tipo

TSource

Tipo de los elementos de las secuencias de entrada.The type of the elements of the input sequences.

Parámetros

first
IEnumerable<TSource>

IEnumerable<T> cuyos elementos que no se encuentren en second se van a devolver.An IEnumerable<T> whose elements that are not also in second will be returned.

second
IEnumerable<TSource>

IEnumerable<T> cuyos elementos que también aparecen en la primera secuencia harán que se quiten esos elementos de la secuencia devuelta.An IEnumerable<T> whose elements that also occur in the first sequence will cause those elements to be removed from the returned sequence.

Devoluciones

IEnumerable<TSource>

Una secuencia que contiene la diferencia de conjuntos de los elementos de dos secuencias.A sequence that contains the set difference of the elements of two sequences.

Excepciones

Ejemplos

En el ejemplo de código siguiente se muestra cómo Except<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) utilizar el método para comparar dos secuencias de números y devolver elementos que solo aparecen en la primera secuencia.The following code example demonstrates how to use the Except<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) method to compare two sequences of numbers and return elements that appear only in the first sequence.

double[] numbers1 = { 2.0, 2.0, 2.1, 2.2, 2.3, 2.3, 2.4, 2.5 };
double[] numbers2 = { 2.2 };

IEnumerable<double> onlyInFirstSet = numbers1.Except(numbers2);

foreach (double number in onlyInFirstSet)
    Console.WriteLine(number);

/*
 This code produces the following output:

 2
 2.1
 2.3
 2.4
 2.5
*/
' Create two arrays of doubles.
Dim numbers1() As Double = { 2.0, 2.0, 2.1, 2.2, 2.3, 2.3, 2.4, 2.5 }
Dim numbers2() As Double = {2.2}

' Select the elements from the first array that are not
' in the second array.
Dim onlyInFirstSet As IEnumerable(Of Double) = numbers1.Except(numbers2)

Dim output As New System.Text.StringBuilder
For Each number As Double In onlyInFirstSet
    output.AppendLine(number)
Next

' Display the output.
MsgBox(output.ToString())

' This code produces the following output:
'
' 2
' 2.1
' 2.3
' 2.4
' 2.5

Si desea comparar secuencias de objetos de algún tipo de datos personalizado, tiene que implementar la IEquatable<T> interfaz genérica en una clase auxiliar.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. En el ejemplo de código siguiente se muestra cómo implementar esta interfaz en un tipo de datos GetHashCode personalizado Equals e invalidar y métodos.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

Después de implementar esta interfaz, puede usar secuencias de ProductA objetos en el Except<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) método, como se muestra en el ejemplo siguiente:After you implement this interface, you can use sequences of ProductA objects in the Except<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) method, as shown in the following example:

ProductA[] fruits1 = { new ProductA { Name = "apple", Code = 9 }, 
                       new ProductA { Name = "orange", Code = 4 },
                        new ProductA { Name = "lemon", Code = 12 } };

ProductA[] fruits2 = { new ProductA { Name = "apple", Code = 9 } };

//Get all the elements from the first array
//except for the elements from the second array.

IEnumerable<ProductA> except =
    fruits1.Except(fruits2);

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

/*
  This code produces the following output:
 
  orange 4
  lemon 12
*/
Dim fruits1() As Product = 
    {New Product With {.Name = "apple", .Code = 9}, 
     New Product With {.Name = "orange", .Code = 4}, 
     New Product With {.Name = "lemon", .Code = 12}}

Dim fruits2() As Product = 
    {New Product With {.Name = "apple", .Code = 9}}

' Get all the elements from the first array
' except for the elements from the second array.

Dim except = fruits1.Except(fruits2)

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

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

Comentarios

Este método se implementa mediante la ejecución aplazada.This method is implemented by using deferred execution. El valor devuelto inmediato es un objeto que almacena toda la información necesaria para realizar la acción.The immediate return value is an object that stores all the information that is required to perform the action. La consulta representada por este método no se ejecuta hasta que el objeto se enumera llamando a GetEnumerator su método directamente o usando foreach en Visual C# o For Each en 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.

El comparador de igualdad Defaultpredeterminado,, se usa para comparar los valores de los tipos.The default equality comparer, Default, is used to compare values of the types. Para comparar un tipo de datos personalizado, debe invalidar los Equals GetHashCode métodos y y, opcionalmente, implementar la IEquatable<T> interfaz genérica en el tipo personalizado.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. Para obtener más información, vea la propiedad Default.For more information, see the Default property.

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

Proporciona la diferencia de conjuntos de dos secuencias utilizando el objeto IEqualityComparer<T> especificado para comparar los valores.Produces the set difference 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> ^ Except(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> Except<TSource> (this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TSource> second, System.Collections.Generic.IEqualityComparer<TSource> comparer);
static member Except : seq<'Source> * seq<'Source> * System.Collections.Generic.IEqualityComparer<'Source> -> seq<'Source>
<Extension()>
Public Function Except(Of TSource) (first As IEnumerable(Of TSource), second As IEnumerable(Of TSource), comparer As IEqualityComparer(Of TSource)) As IEnumerable(Of TSource)

Parámetros de tipo

TSource

Tipo de los elementos de las secuencias de entrada.The type of the elements of the input sequences.

Parámetros

first
IEnumerable<TSource>

IEnumerable<T> cuyos elementos que no se encuentren en second se van a devolver.An IEnumerable<T> whose elements that are not also in second will be returned.

second
IEnumerable<TSource>

IEnumerable<T> cuyos elementos que también aparecen en la primera secuencia harán que se quiten esos elementos de la secuencia devuelta.An IEnumerable<T> whose elements that also occur in the first sequence will cause those elements to be removed from the returned sequence.

comparer
IEqualityComparer<TSource>

IEqualityComparer<T> para comparar valores.An IEqualityComparer<T> to compare values.

Devoluciones

IEnumerable<TSource>

Una secuencia que contiene la diferencia de conjuntos de los elementos de dos secuencias.A sequence that contains the set difference of the elements of two sequences.

Excepciones

Ejemplos

Si desea comparar secuencias de objetos de algún tipo de datos personalizado, tiene que implementar la IEqualityComparer<T> interfaz genérica en una clase auxiliar.If you want to compare sequences of objects of some custom data type, you have to implement the IEqualityComparer<T> generic interface in a helper class. En el ejemplo de código siguiente se muestra cómo implementar esta interfaz en un tipo de datos GetHashCode personalizado Equals y se proporcionan los métodos y.The following code example shows how to implement this interface in a custom data type and provide GetHashCode and Equals methods. En el ejemplo siguiente se muestra cómo implementar un comparador de igualdad que se puede Except utilizar en el método.The following example shows how to implement an equality comparer that can be used in the Except 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

Después de implementar este comparador, puede usar secuencias de Product objetos en el Except método, como se muestra en el ejemplo siguiente:After you implement this comparer, you can use sequences of Product objects in the Except method, as shown in the following example:

Product[] fruits1 = { new Product { Name = "apple", Code = 9 }, 
                       new Product { Name = "orange", Code = 4 },
                        new Product { Name = "lemon", Code = 12 } };

Product[] fruits2 = { new Product { Name = "apple", Code = 9 } };

//Get all the elements from the first array
//except for the elements from the second array.

IEnumerable<Product> except =
    fruits1.Except(fruits2, new ProductComparer());

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

/*
  This code produces the following output:
 
  orange 4
  lemon 12
*/

Dim fruits1() As Product = 
    {New Product With {.Name = "apple", .Code = 9}, 
     New Product With {.Name = "orange", .Code = 4}, 
     New Product With {.Name = "lemon", .Code = 12}}

Dim fruits2() As Product = 
    {New Product With {.Name = "apple", .Code = 9}}

' Get all the elements from the first array
' except for the elements from the second array.

Dim except = fruits1.Except(fruits2, New ProductComparer())

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

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

Comentarios

Si comparer Defaultes null, se utiliza el comparador de igualdad predeterminado,, para comparar los valores.If comparer is null, the default equality comparer, Default, is used to compare values.

Se aplica a