Enumerable.Union Enumerable.Union Enumerable.Union Enumerable.Union Method

定義

2 つのシーケンスの和集合を生成します。Produces the set union of two sequences.

オーバーロード

Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)

既定の等値比較子を使用して、2 つのシーケンスの和集合を生成します。Produces the set union of two sequences by using the default equality comparer.

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

指定された IEqualityComparer<T> を使用して 2 つのシーケンスの和集合を生成します。Produces the set union of two sequences by using a specified IEqualityComparer<T>.

注釈

注意

この記事の C# 例の一部は、Try.NET インライン コード ランナーとプレイグラウンドで実行されます。Some of the C# examples in this article run in the Try.NET inline code runner and playground. [実行] ボタンがある場合は、これを選択して対話型ウィンドウで例を実行します。When present, select the Run button to run an example in an interactive window. コードを実行したら、コードを変更し、[実行] をもう一度選択して変更後のコードを実行できます。Once you execute the code, you can modify it and run the modified code by selecting Run again. 変更後のコードが対話型ウィンドウで実行されるか、コンパイルできなかった場合、対話型ウィンドウにすべての C# コンパイラ エラー メッセージが表示されます。The modified code either runs in the interactive window or, if compilation fails, the interactive window displays all C# compiler error messages.

Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)

既定の等値比較子を使用して、2 つのシーケンスの和集合を生成します。Produces the set union of two sequences by using the default equality comparer.

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

型パラメーター

TSource

入力シーケンスの要素の型。The type of the elements of the input sequences.

パラメーター

first
IEnumerable<TSource>

和集合の最初のセットを形成する一意の要素を含む IEnumerable<T>An IEnumerable<T> whose distinct elements form the first set for the union.

second
IEnumerable<TSource>

和集合の 2 番目のセットを形成する一意の要素を含む IEnumerable<T>An IEnumerable<T> whose distinct elements form the second set for the union.

戻り値

IEnumerable<TSource>

2 つの入力シーケンスの要素 (重複する要素は除く) を格納している IEnumerable<T>An IEnumerable<T> that contains the elements from both input sequences, excluding duplicates.

例外

first または secondnull です。first or second is null.

次のコード例は、使用する方法を示しますUnion<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)整数の 2 つのシーケンスの和集合を取得します。The following code example demonstrates how to use Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) to obtain the union of two sequences of integers.

int[] ints1 = { 5, 3, 9, 7, 5, 9, 3, 7 };
int[] ints2 = { 8, 3, 6, 4, 4, 9, 1, 0 };

IEnumerable<int> union = ints1.Union(ints2);

foreach (int num in union)
{
    Console.Write("{0} ", num);
}

/*
 This code produces the following output:

 5 3 9 7 8 6 4 1 0
*/
' Create two arrays of integer values.
Dim ints1() As Integer = {5, 3, 9, 7, 5, 9, 3, 7}
Dim ints2() As Integer = {8, 3, 6, 4, 4, 9, 1, 0}

' Get the set union of the two arrays.
Dim union As IEnumerable(Of Integer) = ints1.Union(ints2)

' Display the resulting set's values.
Dim output As New System.Text.StringBuilder
For Each num As Integer In union
    output.AppendLine(num & " ")
Next
MsgBox(output.ToString())

' This code produces the following output:
'
' 5 
' 3 
' 9 
' 7 
' 8 
' 6 
' 4 
' 1 
' 0 

実装する必要があるいくつかのカスタム データ型のオブジェクトのシーケンスを比較する場合は、IEquatable<T>ヘルパー クラスでジェネリック インターフェイス。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. 次のコード例は、カスタム データ型にこのインターフェイスを実装し、オーバーライドする方法を示しています。GetHashCodeEqualsメソッド。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

このインターフェイスを実装した後のシーケンスを使用することができますProductA内のオブジェクト、Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)メソッドを次の例に示すようにします。After you implement this interface, you can use sequences of ProductA objects in the Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) method, as shown in the following example:

ProductA[] store1 = { new ProductA { Name = "apple", Code = 9 }, 
                       new ProductA { Name = "orange", Code = 4 } };

ProductA[] store2 = { new ProductA { Name = "apple", Code = 9 }, 
                       new ProductA { Name = "lemon", Code = 12 } };
Dim store1() As ProductA = 
    {New Product With {.Name = "apple", .Code = 9}, 
     New Product With {.Name = "orange", .Code = 4}}

Dim store2() As ProductA = 
    {New Product With {.Name = "apple", .Code = 9}, 
     New Product With {.Name = "lemon", .Code = 12}}
//Get the products from the both arrays
//excluding duplicates.

IEnumerable<ProductA> union =
  store1.Union(store2);

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

/*
    This code produces the following output:
 
    apple 9
    orange 4
    lemon 12
*/
' Get the products from the both arrays
' excluding duplicates.

Dim union = store1.Union(store2)

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

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

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. 即時の戻り値は、操作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.

このメソッドは、戻り値のセットから重複を除外します。This method excludes duplicates from the return set. これは、異なる動作をConcatメソッドで、重複を含めて入力シーケンスのすべての要素を返します。This is different behavior to the Concat method, which returns all the elements in the input sequences including duplicates.

既定の等値比較子Default、実装する型の値を比較するために使用、IEqualityComparer<T>ジェネリック インターフェイス。The default equality comparer, Default, is used to compare values of the types that implement the IEqualityComparer<T> generic interface. カスタム データ型を比較する必要がありますをこのインターフェイスを実装し、独自GetHashCodeEquals型のメソッド。To compare a custom data type, you need to implement this interface and provide your own GetHashCode and Equals methods for the type.

このメソッドによって返されるオブジェクトが列挙されたときにUnion列挙firstsecondをこの順序で既に生成されていない各の要素を生成します。When the object returned by this method is enumerated, Union enumerates first and second in that order and yields each element that has not already been yielded.

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

指定された IEqualityComparer<T> を使用して 2 つのシーケンスの和集合を生成します。Produces the set union of two sequences by using a specified IEqualityComparer<T>.

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

型パラメーター

TSource

入力シーケンスの要素の型。The type of the elements of the input sequences.

パラメーター

first
IEnumerable<TSource>

和集合の最初のセットを形成する一意の要素を含む IEnumerable<T>An IEnumerable<T> whose distinct elements form the first set for the union.

second
IEnumerable<TSource>

和集合の 2 番目のセットを形成する一意の要素を含む IEnumerable<T>An IEnumerable<T> whose distinct elements form the second set for the union.

comparer
IEqualityComparer<TSource>

値を比較する IEqualityComparer<T>The IEqualityComparer<T> to compare values.

戻り値

IEnumerable<TSource>

2 つの入力シーケンスの要素 (重複する要素は除く) を格納している IEnumerable<T>An IEnumerable<T> that contains the elements from both input sequences, excluding duplicates.

例外

first または secondnull です。first or second is null.

次の例で使用できる等値比較子を実装する方法を示しています、Unionメソッド。The following example shows how to implement an equality comparer that can be used in the Union 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

この比較演算子を実装すると後のシーケンスを使用することができますProduct内のオブジェクト、Unionメソッドを次の例に示すようにします。After you implement this comparer, you can use sequences of Product objects in the Union method, as shown in the following example:

Product[] store1 = { new Product { Name = "apple", Code = 9 }, 
                       new Product { Name = "orange", Code = 4 } };

Product[] store2 = { new Product { Name = "apple", Code = 9 }, 
                       new Product { Name = "lemon", Code = 12 } };
Dim store1() As Product = 
    {New Product With {.Name = "apple", .Code = 9}, 
     New Product With {.Name = "orange", .Code = 4}}

Dim store2() As Product = 
    {New Product With {.Name = "apple", .Code = 9}, 
     New Product With {.Name = "lemon", .Code = 12}}
//Get the products from the both arrays
//excluding duplicates.

IEnumerable<Product> union =
  store1.Union(store2, new ProductComparer());

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

/*
    This code produces the following output:
 
    apple 9
    orange 4
    lemon 12
*/
' Get the products from the both arrays
' excluding duplicates.

Dim union = store1.Union(store2, New ProductComparer())

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

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

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. 即時の戻り値は、操作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.

場合comparernull、既定の等値比較子Default値を比較するために使用します。If comparer is null, the default equality comparer, Default, is used to compare values.

このメソッドによって返されるオブジェクトが列挙されたときにUnion列挙firstsecondをこの順序で既に生成されていない各の要素を生成します。When the object returned by this method is enumerated, Union enumerates first and second in that order and yields each element that has not already been yielded.

Concatメソッドとは異なります、Unionメソッドのため、Concatメソッドは、一方で重複を含む、入力シーケンス内のすべての要素を返しますUnion一意の値のみを返します。The Concat method differs from the Union method because the Concat method returns all the elements in the input sequences including duplicates, whereas Union returns only unique values.

適用対象