Enumerable.Join メソッド

定義

一致するキーに基づいて 2 つのシーケンスの要素を相互に関連付けます。Correlates the elements of two sequences based on matching keys.

オーバーロード

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

一致するキーに基づいて 2 つのシーケンスの要素を相互に関連付けます。Correlates the elements of two sequences based on matching keys. キーの比較には既定の等値比較子が使用されます。The default equality comparer is used to compare keys.

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

一致するキーに基づいて 2 つのシーケンスの要素を相互に関連付けます。Correlates the elements of two sequences based on matching keys. 指定された IEqualityComparer<T> を使用してキーを比較します。A specified IEqualityComparer<T> is used to compare keys.

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

一致するキーに基づいて 2 つのシーケンスの要素を相互に関連付けます。Correlates the elements of two sequences based on matching keys. キーの比較には既定の等値比較子が使用されます。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> ^ Join(System::Collections::Generic::IEnumerable<TOuter> ^ outer, System::Collections::Generic::IEnumerable<TInner> ^ inner, Func<TOuter, TKey> ^ outerKeySelector, Func<TInner, TKey> ^ innerKeySelector, Func<TOuter, TInner, TResult> ^ resultSelector);
public static System.Collections.Generic.IEnumerable<TResult> Join<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,TInner,TResult> resultSelector);
static member Join : seq<'Outer> * seq<'Inner> * Func<'Outer, 'Key> * Func<'Inner, 'Key> * Func<'Outer, 'Inner, 'Result> -> seq<'Result>
<Extension()>
Public Function Join(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, TInner, TResult)) As IEnumerable(Of TResult)

型パラメーター

TOuter

最初のシーケンスの要素の型。The type of the elements of the first sequence.

TInner

2 番目のシーケンスの要素の型。The type of the elements of the second sequence.

TKey

キー セレクター関数によって返されるキーの型。The type of the keys returned by the key selector functions.

TResult

結果の要素の型。The type of the result elements.

パラメーター

outer
IEnumerable<TOuter>

結合する最初のシーケンス。The first sequence to join.

inner
IEnumerable<TInner>

最初のシーケンスに結合するシーケンス。The sequence to join to the first sequence.

outerKeySelector
Func<TOuter,TKey>

最初のシーケンスの各要素から結合キーを抽出する関数。A function to extract the join key from each element of the first sequence.

innerKeySelector
Func<TInner,TKey>

2 番目のシーケンスの各要素から結合キーを抽出する関数。A function to extract the join key from each element of the second sequence.

resultSelector
Func<TOuter,TInner,TResult>

一致する 2 つの要素から結果の要素を作成する関数。A function to create a result element from two matching elements.

戻り値

IEnumerable<TResult>

2 つのシーケンスに対して内部結合を実行して取得する、TResult 型の要素が格納されている IEnumerable<T>An IEnumerable<T> that has elements of type TResult that are obtained by performing an inner join on two sequences.

例外

outerinnerouterKeySelectorinnerKeySelector、または resultSelectornull です。outer or inner or outerKeySelector or innerKeySelector or resultSelector is null.

次のコード例では、Join<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,TInner,TResult>) を使用して、共通キーに基づいて2つのシーケンスの内部結合を実行する方法を示します。The following code example demonstrates how to use Join<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,TInner,TResult>) to perform an inner join of two sequences based on a common key.

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

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

public static void JoinEx1()
{
    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 of Person-Pet pairs where 
    // each element is an anonymous type that contains a
    // Pet's name and the name of the Person that owns the Pet.
    var query =
        people.Join(pets,
                    person => person,
                    pet => pet.Owner,
                    (person, pet) =>
                        new { OwnerName = person.Name, Pet = pet.Name });

    foreach (var obj in query)
    {
        Console.WriteLine(
            "{0} - {1}",
            obj.OwnerName,
            obj.Pet);
    }
}

/*
 This code produces the following output:

 Hedlund, Magnus - Daisy
 Adams, Terry - Barley
 Adams, Terry - 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 JoinEx1()
    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 list of Person-Pet pairs, where each element is an
    ' anonymous type that contains a Pet's name and the name of the 
    ' Person that owns the Pet.
    Dim query =
people.Join(pets,
            Function(person) person,
            Function(pet) pet.Owner,
            Function(person, pet) _
                New With {.OwnerName = person.Name, .Pet = pet.Name})

    Dim output As New System.Text.StringBuilder
    For Each obj In query
        output.AppendLine(obj.OwnerName & " - " & obj.Pet)
    Next

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

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

注釈

このメソッドは、遅延実行を使用して実装されます。This method is implemented by using deferred execution. イミディエイトの戻り値は、アクションを実行するために必要なすべての情報を格納するオブジェクトです。The immediate return value is an object that stores all the information that is required to perform the action. か、呼び出すことによって、オブジェクトが列挙されるまで、このメソッドによって表されるクエリは実行されません、GetEnumeratorメソッドを使用して直接またはforeachVisual C# またはFor EachVisual Basic で。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.

既定の等値比較子 (@no__t 0) は、キーのハッシュと比較に使用されます。The default equality comparer, Default, is used to hash and compare keys.

結合とは、共通のキーに基づいて、2つの情報ソースの要素を相互に関連付ける操作を指します。A join refers to the operation of correlating the elements of two sources of information based on a common key. Join を指定すると、2つの情報ソースとキーが1つのメソッド呼び出しで一致するようになります。Join brings the two information sources and the keys by which they are matched together in one method call. これは、同じ操作を実行するために複数のメソッド呼び出しを必要とする SelectMany の使用とは異なります。This differs from the use of SelectMany, which requires more than one method call to perform the same operation.

Join @no__t の要素の順序を保持します。これらの各要素について、inner の一致する要素の順序を保持します。Join preserves the order of the elements of outer, and for each of these elements, the order of the matching elements of inner.

クエリ式の構文で、 join (Visual C#) またはJoinの呼び出しに変換します (Visual Basic) 句Joinします。In query expression syntax, a join (Visual C#) or Join (Visual Basic) clause translates to an invocation of Join.

リレーショナルデータベース用語では、@no__t 0 メソッドは内部等結合を実装します。In relational database terms, the Join method implements an inner equijoin. ' Inner ' は、他のシーケンスと一致する要素だけが結果に含まれることを意味します。'Inner' means that only elements that have a match in the other sequence are included in the results. ' 等結合 ' は、キーが等しいかどうかを比較する結合です。An 'equijoin' is a join in which the keys are compared for equality. 左外部結合操作には専用の標準クエリ演算子はありませんが、GroupJoin メソッドを使用して実行できます。A left outer join operation has no dedicated standard query operator, but can be performed by using the GroupJoin method. 結合操作」を参照してください。See Join Operations.

こちらもご覧ください

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

一致するキーに基づいて 2 つのシーケンスの要素を相互に関連付けます。Correlates the elements of two sequences based on matching keys. 指定された IEqualityComparer<T> を使用してキーを比較します。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> ^ Join(System::Collections::Generic::IEnumerable<TOuter> ^ outer, System::Collections::Generic::IEnumerable<TInner> ^ inner, Func<TOuter, TKey> ^ outerKeySelector, Func<TInner, TKey> ^ innerKeySelector, Func<TOuter, TInner, TResult> ^ resultSelector, System::Collections::Generic::IEqualityComparer<TKey> ^ comparer);
public static System.Collections.Generic.IEnumerable<TResult> Join<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,TInner,TResult> resultSelector, System.Collections.Generic.IEqualityComparer<TKey> comparer);
static member Join : seq<'Outer> * seq<'Inner> * Func<'Outer, 'Key> * Func<'Inner, 'Key> * Func<'Outer, 'Inner, 'Result> * System.Collections.Generic.IEqualityComparer<'Key> -> seq<'Result>
<Extension()>
Public Function Join(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, TInner, TResult), comparer As IEqualityComparer(Of TKey)) As IEnumerable(Of TResult)

型パラメーター

TOuter

最初のシーケンスの要素の型。The type of the elements of the first sequence.

TInner

2 番目のシーケンスの要素の型。The type of the elements of the second sequence.

TKey

キー セレクター関数によって返されるキーの型。The type of the keys returned by the key selector functions.

TResult

結果の要素の型。The type of the result elements.

パラメーター

outer
IEnumerable<TOuter>

結合する最初のシーケンス。The first sequence to join.

inner
IEnumerable<TInner>

最初のシーケンスに結合するシーケンス。The sequence to join to the first sequence.

outerKeySelector
Func<TOuter,TKey>

最初のシーケンスの各要素から結合キーを抽出する関数。A function to extract the join key from each element of the first sequence.

innerKeySelector
Func<TInner,TKey>

2 番目のシーケンスの各要素から結合キーを抽出する関数。A function to extract the join key from each element of the second sequence.

resultSelector
Func<TOuter,TInner,TResult>

一致する 2 つの要素から結果の要素を作成する関数。A function to create a result element from two matching elements.

comparer
IEqualityComparer<TKey>

キーをハッシュして比較する IEqualityComparer<T>An IEqualityComparer<T> to hash and compare keys.

戻り値

IEnumerable<TResult>

2 つのシーケンスに対して内部結合を実行して取得する、TResult 型の要素が格納されている IEnumerable<T>An IEnumerable<T> that has elements of type TResult that are obtained by performing an inner join on two sequences.

例外

outerinnerouterKeySelectorinnerKeySelector、または resultSelectornull です。outer or inner or outerKeySelector or innerKeySelector or resultSelector is null.

注釈

このメソッドは、遅延実行を使用して実装されます。This method is implemented by using deferred execution. イミディエイトの戻り値は、アクションを実行するために必要なすべての情報を格納するオブジェクトです。The immediate return value is an object that stores all the information that is required to perform the action. か、呼び出すことによって、オブジェクトが列挙されるまで、このメソッドによって表されるクエリは実行されません、GetEnumeratorメソッドを使用して直接またはforeachVisual C# またはFor EachVisual Basic で。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.

@No__t-0 が null の場合は、既定の等値比較子 (Default) を使用して、キーのハッシュと比較を行います。If comparer is null, the default equality comparer, Default, is used to hash and compare keys.

結合とは、共通のキーに基づいて、2つの情報ソースの要素を相互に関連付ける操作を指します。A join refers to the operation of correlating the elements of two sources of information based on a common key. Join を指定すると、2つの情報ソースとキーが1つのメソッド呼び出しで一致するようになります。Join brings the two information sources and the keys by which they are matched together in one method call. これは、同じ操作を実行するために複数のメソッド呼び出しを必要とする SelectMany の使用とは異なります。This differs from the use of SelectMany, which requires more than one method call to perform the same operation.

Join @no__t の要素の順序を保持します。これらの各要素について、inner の一致する要素の順序を保持します。Join preserves the order of the elements of outer, and for each of these elements, the order of the matching elements of inner.

リレーショナルデータベース用語では、@no__t 0 メソッドは内部等結合を実装します。In relational database terms, the Join method implements an inner equijoin. ' Inner ' は、他のシーケンスと一致する要素だけが結果に含まれることを意味します。'Inner' means that only elements that have a match in the other sequence are included in the results. ' 等結合 ' は、キーが等しいかどうかを比較する結合です。An 'equijoin' is a join in which the keys are compared for equality. 左外部結合操作には専用の標準クエリ演算子はありませんが、GroupJoin メソッドを使用して実行できます。A left outer join operation has no dedicated standard query operator, but can be performed by using the GroupJoin method. 結合操作」を参照してください。See Join Operations.

こちらもご覧ください

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