Enumerable.GroupJoin Enumerable.GroupJoin Enumerable.GroupJoin Enumerable.GroupJoin Method

Definición

Establece una correlación entre los elementos de dos secuencias en función de la igualdad de sus claves y agrupa los resultados.Correlates the elements of two sequences based on key equality, and groups the results.

Sobrecargas

GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>,TResult>, IEqualityComparer<TKey>) GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>,TResult>, IEqualityComparer<TKey>) GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>,TResult>, IEqualityComparer<TKey>) GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>,TResult>, IEqualityComparer<TKey>)

Establece una correlación entre los elementos de dos secuencias basándose en la igualdad de clave y agrupa los resultados.Correlates the elements of two sequences based on key equality and groups the results. Se usa un IEqualityComparer<T> especificado para comparar claves.A specified IEqualityComparer<T> is used to compare keys.

GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>,TResult>) GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>,TResult>) GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>,TResult>) GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>,TResult>)

Establece una correlación entre los elementos de dos secuencias en función de la igualdad de sus claves y agrupa los resultados.Correlates the elements of two sequences based on equality of keys and groups the results. El comparador de igualdad predeterminado se usa para comparar claves.The default equality comparer is used to compare keys.

GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>,TResult>, IEqualityComparer<TKey>) GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>,TResult>, IEqualityComparer<TKey>) GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>,TResult>, IEqualityComparer<TKey>) GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>,TResult>, IEqualityComparer<TKey>)

Establece una correlación entre los elementos de dos secuencias basándose en la igualdad de clave y agrupa los resultados.Correlates the elements of two sequences based on key equality and groups the results. Se usa un IEqualityComparer<T> especificado para comparar claves.A specified IEqualityComparer<T> is used to compare keys.

public:
generic <typename TOuter, typename TInner, typename TKey, typename TResult>
[System::Runtime::CompilerServices::Extension]
 static System::Collections::Generic::IEnumerable<TResult> ^ GroupJoin(System::Collections::Generic::IEnumerable<TOuter> ^ outer, System::Collections::Generic::IEnumerable<TInner> ^ inner, Func<TOuter, TKey> ^ outerKeySelector, Func<TInner, TKey> ^ innerKeySelector, Func<TOuter, System::Collections::Generic::IEnumerable<TInner> ^, TResult> ^ resultSelector, System::Collections::Generic::IEqualityComparer<TKey> ^ comparer);
public static System.Collections.Generic.IEnumerable<TResult> GroupJoin<TOuter,TInner,TKey,TResult> (this System.Collections.Generic.IEnumerable<TOuter> outer, System.Collections.Generic.IEnumerable<TInner> inner, Func<TOuter,TKey> outerKeySelector, Func<TInner,TKey> innerKeySelector, Func<TOuter,System.Collections.Generic.IEnumerable<TInner>,TResult> resultSelector, System.Collections.Generic.IEqualityComparer<TKey> comparer);
static member GroupJoin : seq<'Outer> * seq<'Inner> * Func<'Outer, 'Key> * Func<'Inner, 'Key> * Func<'Outer, seq<'Inner>, 'Result> * System.Collections.Generic.IEqualityComparer<'Key> -> seq<'Result>
<Extension()>
Public Function GroupJoin(Of TOuter, TInner, TKey, TResult) (outer As IEnumerable(Of TOuter), inner As IEnumerable(Of TInner), outerKeySelector As Func(Of TOuter, TKey), innerKeySelector As Func(Of TInner, TKey), resultSelector As Func(Of TOuter, IEnumerable(Of TInner), TResult), comparer As IEqualityComparer(Of TKey)) As IEnumerable(Of TResult)

Parámetros de tipo

TOuter

Tipo de los elementos de la primera secuencia.The type of the elements of the first sequence.

TInner

Tipo de los elementos de la segunda secuencia.The type of the elements of the second sequence.

TKey

Tipo de las claves devueltas por las funciones del selector de claves.The type of the keys returned by the key selector functions.

TResult

Tipo de los elementos del resultado.The type of the result elements.

Parámetros

outer
IEnumerable<TOuter>

Primera secuencia que se va a combinar.The first sequence to join.

inner
IEnumerable<TInner>

Secuencia que se va a combinar con la primera secuencia.The sequence to join to the first sequence.

outerKeySelector
Func<TOuter,TKey>

Función para extraer la clave de combinación a partir de cada elemento de la primera secuencia.A function to extract the join key from each element of the first sequence.

innerKeySelector
Func<TInner,TKey>

Función para extraer la clave de combinación a partir de cada elemento de la segunda secuencia.A function to extract the join key from each element of the second sequence.

resultSelector
Func<TOuter,IEnumerable<TInner>,TResult>

Función para crear un elemento de resultado a partir de un elemento de la primera secuencia y una colección de elementos coincidentes de la segunda.A function to create a result element from an element from the first sequence and a collection of matching elements from the second sequence.

comparer
IEqualityComparer<TKey>

IEqualityComparer<T> que va a aplicar un algoritmo hash y a comparar las claves.An IEqualityComparer<T> to hash and compare keys.

Devoluciones

IEnumerable<TResult>

IEnumerable<T> que contiene elementos de tipo TResult que se han obtenido al realizar una combinación agrupada de dos secuencias.An IEnumerable<T> that contains elements of type TResult that are obtained by performing a grouped join on two sequences.

Excepciones

outer o inner o outerKeySelector o innerKeySelector o resultSelector es null.outer or inner or outerKeySelector or innerKeySelector or resultSelector is null.

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.

Si comparer Defaultes null, el comparador de igualdad predeterminado,, se usa para aplicar un algoritmo hash y comparar claves.If comparer is null, the default equality comparer, Default, is used to hash and compare keys.

GroupJoingenera resultados jerárquicos, lo que significa que los outer elementos de se emparejan con colecciones de elementos innercoincidentes de.GroupJoin produces hierarchical results, which means that elements from outer are paired with collections of matching elements from inner. GroupJoinpermite basar los resultados en un conjunto completo de coincidencias para cada elemento outerde.GroupJoin enables you to base your results on a whole set of matches for each element of outer.

Nota

Si no hay elementos correlacionados en inner para un elemento determinado de outer, la secuencia de coincidencias para ese elemento estará vacía, pero seguirá apareciendo en los resultados.If there are no correlated elements in inner for a given element of outer, the sequence of matches for that element will be empty but will still appear in the results.

Solo resultSelector se llama a la función una vez para outer cada elemento junto con inner una colección de todos los elementos que coinciden con el outer elemento.The resultSelector function is called only one time for each outer element together with a collection of all the inner elements that match the outer element. Esto difiere Join del método en el que la función del selector de resultados se invoca en pares que contienen un elemento outer de y un elemento innerde.This differs from the Join method in which the result selector function is invoked on pairs that contain one element from outer and one element from inner.

GroupJoinconserva el orden de los elementos de outer, y para cada elemento de outer, el orden de los elementos coincidentes de inner.GroupJoin preserves the order of the elements of outer, and for each element of outer, the order of the matching elements from inner.

GroupJoinno tiene ningún equivalente directo en términos de bases de datos relacionales tradicionales.GroupJoin has no direct equivalent in traditional relational database terms. Sin embargo, este método implementa un supraconjunto de combinaciones internas y combinaciones externas izquierdas.However, this method does implement a superset of inner joins and left outer joins. Ambas operaciones se pueden escribir en términos de una combinación agrupada.Both of these operations can be written in terms of a grouped join. Vea operaciones de combinación.See Join Operations.

Consulte también:

GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>,TResult>) GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>,TResult>) GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>,TResult>) GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>,TResult>)

Establece una correlación entre los elementos de dos secuencias en función de la igualdad de sus claves y agrupa los resultados.Correlates the elements of two sequences based on equality of keys and groups the results. El comparador de igualdad predeterminado se usa para comparar claves.The default equality comparer is used to compare keys.

public:
generic <typename TOuter, typename TInner, typename TKey, typename TResult>
[System::Runtime::CompilerServices::Extension]
 static System::Collections::Generic::IEnumerable<TResult> ^ GroupJoin(System::Collections::Generic::IEnumerable<TOuter> ^ outer, System::Collections::Generic::IEnumerable<TInner> ^ inner, Func<TOuter, TKey> ^ outerKeySelector, Func<TInner, TKey> ^ innerKeySelector, Func<TOuter, System::Collections::Generic::IEnumerable<TInner> ^, TResult> ^ resultSelector);
public static System.Collections.Generic.IEnumerable<TResult> GroupJoin<TOuter,TInner,TKey,TResult> (this System.Collections.Generic.IEnumerable<TOuter> outer, System.Collections.Generic.IEnumerable<TInner> inner, Func<TOuter,TKey> outerKeySelector, Func<TInner,TKey> innerKeySelector, Func<TOuter,System.Collections.Generic.IEnumerable<TInner>,TResult> resultSelector);
static member GroupJoin : seq<'Outer> * seq<'Inner> * Func<'Outer, 'Key> * Func<'Inner, 'Key> * Func<'Outer, seq<'Inner>, 'Result> -> seq<'Result>
<Extension()>
Public Function GroupJoin(Of TOuter, TInner, TKey, TResult) (outer As IEnumerable(Of TOuter), inner As IEnumerable(Of TInner), outerKeySelector As Func(Of TOuter, TKey), innerKeySelector As Func(Of TInner, TKey), resultSelector As Func(Of TOuter, IEnumerable(Of TInner), TResult)) As IEnumerable(Of TResult)

Parámetros de tipo

TOuter

Tipo de los elementos de la primera secuencia.The type of the elements of the first sequence.

TInner

Tipo de los elementos de la segunda secuencia.The type of the elements of the second sequence.

TKey

Tipo de las claves devueltas por las funciones del selector de claves.The type of the keys returned by the key selector functions.

TResult

Tipo de los elementos del resultado.The type of the result elements.

Parámetros

outer
IEnumerable<TOuter>

Primera secuencia que se va a combinar.The first sequence to join.

inner
IEnumerable<TInner>

Secuencia que se va a combinar con la primera secuencia.The sequence to join to the first sequence.

outerKeySelector
Func<TOuter,TKey>

Función para extraer la clave de combinación a partir de cada elemento de la primera secuencia.A function to extract the join key from each element of the first sequence.

innerKeySelector
Func<TInner,TKey>

Función para extraer la clave de combinación a partir de cada elemento de la segunda secuencia.A function to extract the join key from each element of the second sequence.

resultSelector
Func<TOuter,IEnumerable<TInner>,TResult>

Función para crear un elemento de resultado a partir de un elemento de la primera secuencia y una colección de elementos coincidentes de la segunda.A function to create a result element from an element from the first sequence and a collection of matching elements from the second sequence.

Devoluciones

IEnumerable<TResult>

IEnumerable<T> que contiene elementos de tipo TResult que se han obtenido al realizar una combinación agrupada de dos secuencias.An IEnumerable<T> that contains elements of type TResult that are obtained by performing a grouped join on two sequences.

Excepciones

outer o inner o outerKeySelector o innerKeySelector o resultSelector es null.outer or inner or outerKeySelector or innerKeySelector or resultSelector is null.

Ejemplos

En el ejemplo de código siguiente se muestra GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>,TResult>) cómo utilizar para realizar una combinación agrupada en dos secuencias.The following code example demonstrates how to use GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>,TResult>) to perform a grouped join on two sequences.

class Person
{
    public string Name { get; set; }
}

class Pet
{
    public string Name { get; set; }
    public Person Owner { get; set; }
}

public static void GroupJoinEx1()
{
    Person magnus = new Person { Name = "Hedlund, Magnus" };
    Person terry = new Person { Name = "Adams, Terry" };
    Person charlotte = new Person { Name = "Weiss, Charlotte" };

    Pet barley = new Pet { Name = "Barley", Owner = terry };
    Pet boots = new Pet { Name = "Boots", Owner = terry };
    Pet whiskers = new Pet { Name = "Whiskers", Owner = charlotte };
    Pet daisy = new Pet { Name = "Daisy", Owner = magnus };

    List<Person> people = new List<Person> { magnus, terry, charlotte };
    List<Pet> pets = new List<Pet> { barley, boots, whiskers, daisy };

    // Create a list where each element is an anonymous 
    // type that contains a person's name and 
    // a collection of names of the pets they own.
    var query =
        people.GroupJoin(pets,
                         person => person,
                         pet => pet.Owner,
                         (person, petCollection) =>
                             new
                             {
                                 OwnerName = person.Name,
                                 Pets = petCollection.Select(pet => pet.Name)
                             });

    foreach (var obj in query)
    {
        // Output the owner's name.
        Console.WriteLine("{0}:", obj.OwnerName);
        // Output each of the owner's pet's names.
        foreach (string pet in obj.Pets)
        {
            Console.WriteLine("  {0}", pet);
        }
    }
}

/*
 This code produces the following output:

 Hedlund, Magnus:
   Daisy
 Adams, Terry:
   Barley
   Boots
 Weiss, Charlotte:
   Whiskers
*/
Structure Person
    Public Name As String
End Structure

Structure Pet
    Public Name As String
    Public Owner As Person
End Structure

Sub GroupJoinEx1()
    Dim magnus As New Person With {.Name = "Hedlund, Magnus"}
    Dim terry As New Person With {.Name = "Adams, Terry"}
    Dim charlotte As New Person With {.Name = "Weiss, Charlotte"}

    Dim barley As New Pet With {.Name = "Barley", .Owner = terry}
    Dim boots As New Pet With {.Name = "Boots", .Owner = terry}
    Dim whiskers As New Pet With {.Name = "Whiskers", .Owner = charlotte}
    Dim daisy As New Pet With {.Name = "Daisy", .Owner = magnus}

    Dim people As New List(Of Person)(New Person() {magnus, terry, charlotte})
    Dim pets As New List(Of Pet)(New Pet() {barley, boots, whiskers, daisy})

    ' Create a collection where each element is an anonymous type
    ' that contains a Person's name and a collection of names of 
    ' the pets that are owned by them.
    Dim query =
people.GroupJoin(pets,
           Function(person) person,
           Function(pet) pet.Owner,
           Function(person, petCollection) _
               New With {.OwnerName = person.Name,
                         .Pets = petCollection.Select(
                                            Function(pet) pet.Name)})

    Dim output As New System.Text.StringBuilder
    For Each obj In query
        ' Output the owner's name.
        output.AppendLine(obj.OwnerName & ":")
        ' Output each of the owner's pet's names.
        For Each pet As String In obj.Pets
            output.AppendLine("  " & pet)
        Next
    Next

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

' This code produces the following output:
'
' Hedlund, Magnus
'   Daisy
' Adams, Terry
'   Barley
'   Boots
' Weiss, Charlotte
'   Whiskers

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 aplicar un algoritmo hash y comparar claves.The default equality comparer, Default, is used to hash and compare keys.

GroupJoingenera resultados jerárquicos, lo que significa que los outer elementos de se emparejan con colecciones de elementos innercoincidentes de.GroupJoin produces hierarchical results, which means that elements from outer are paired with collections of matching elements from inner. GroupJoinpermite basar los resultados en un conjunto completo de coincidencias para cada elemento outerde.GroupJoin enables you to base your results on a whole set of matches for each element of outer.

Nota

Si no hay elementos correlacionados en inner para un elemento determinado de outer, la secuencia de coincidencias para ese elemento estará vacía, pero seguirá apareciendo en los resultados.If there are no correlated elements in inner for a given element of outer, the sequence of matches for that element will be empty but will still appear in the results.

Solo resultSelector se llama a la función una vez para outer cada elemento junto con inner una colección de todos los elementos que coinciden con el outer elemento.The resultSelector function is called only one time for each outer element together with a collection of all the inner elements that match the outer element. Esto difiere Join del método, en el que la función del selector de resultados se invoca en pares que contienen un elemento outer de y un elemento innerde.This differs from the Join method, in which the result selector function is invoked on pairs that contain one element from outer and one element from inner.

GroupJoinconserva el orden de los elementos de outer, y para cada elemento de outer, el orden de los elementos coincidentes de inner.GroupJoin preserves the order of the elements of outer, and for each element of outer, the order of the matching elements from inner.

GroupJoinno tiene ningún equivalente directo en términos de bases de datos relacionales tradicionales.GroupJoin has no direct equivalent in traditional relational database terms. Sin embargo, este método implementa un supraconjunto de combinaciones internas y combinaciones externas izquierdas.However, this method does implement a superset of inner joins and left outer joins. Ambas operaciones se pueden escribir en términos de una combinación agrupada.Both of these operations can be written in terms of a grouped join. Vea operaciones de combinación.See Join Operations.

En la sintaxis de las expresiones join … into de consulta C#, una Group Join cláusula (visual) o (Visual Basic) se traduce en una GroupJoininvocación de.In query expression syntax, a join … into (Visual C#) or Group Join (Visual Basic) clause translates to an invocation of GroupJoin.

Consulte también:

Se aplica a