Enumerable.SequenceEqual Enumerable.SequenceEqual Enumerable.SequenceEqual Enumerable.SequenceEqual Method

定義

等値比較子に従って 2 つのシーケンスが等しいかどうかを判断します。Determines whether two sequences are equal according to an equality comparer.

オーバーロード

SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)

要素の型に対して既定の等値比較子を使用して要素を比較することで、2 つのシーケンスが等しいかどうかを判断します。Determines whether two sequences are equal by comparing the elements by using the default equality comparer for their type.

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

指定された IEqualityComparer<T> を使用して要素を比較することで、2 つのシーケンスが等しいかどうかを判断します。Determines whether two sequences are equal by comparing their elements by using a specified IEqualityComparer<T>.

SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)

要素の型に対して既定の等値比較子を使用して要素を比較することで、2 つのシーケンスが等しいかどうかを判断します。Determines whether two sequences are equal by comparing the elements by using the default equality comparer for their type.

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

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>

second と比較する IEnumerable<T>An IEnumerable<T> to compare to second.

second
IEnumerable<TSource>

最初のシーケンスと比較する IEnumerable<T>An IEnumerable<T> to compare to the first sequence.

戻り値

2 つのソース シーケンスが同じ長さで、それらに対応する要素がその型の既定の等値比較子に従って等しい場合は true。それ以外の場合は falsetrue if the two source sequences are of equal length and their corresponding elements are equal according to the default equality comparer for their type; otherwise, false.

例外

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

次のコード例では、をSequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)使用して、2つのシーケンスが等しいかどうかを確認する方法を示します。The following code examples demonstrate how to use SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) to determine whether two sequences are equal. 最初の2つの例では、メソッドは、比較対象のシーケンスに同じオブジェクトへの参照が含まれているかどうかを判断します。In the first two examples, the method determines whether the compared sequences contain references to the same objects. 3番目と4番目の例では、メソッドは、シーケンス内のオブジェクトの実際のデータを比較します。In the third and fourth examples, the method compares the actual data of the objects within the sequences.

この例では、シーケンスは同じです。In this example the sequences are equal.

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")
    MsgBox("The lists " & text & " equal.")

End Sub

' This code produces the following output:
'
' The lists are equal.

次のコード例では、等しくない2つのシーケンスを比較します。The following code example compares two sequences that are not equal. シーケンスには同一のデータが含まれていますが、格納されているオブジェクトには異なる参照があるため、これらのシーケンスは等価とは見なされません。Note that the sequences contain identical data, but because the objects that they contain have different references, the sequences are not considered equal.

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")
MsgBox("The lists " & text & " equal.")

' This code produces the following output:
'
' The lists are not equal.

参照を比較するのではなく、シーケンス内のオブジェクトの実際のデータを比較する場合は、 IEqualityComparer<T>ジェネリックインターフェイスをクラスに実装する必要があります。If you want to compare the actual data of the objects in the sequences instead of just comparing their references, you have to implement the IEqualityComparer<T> generic interface in your class. 次のコード例は、ヘルパークラスでこのインターフェイスを実装し、メソッドGetHashCodeEqualsメソッドを提供する方法を示しています。The following code example shows how to implement this interface in a helper class and provide 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、次の例ProductAに示すようSequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)に、メソッドでオブジェクトのシーケンスを使用できます。After you implement this interface, you can use sequences of ProductA objects in the SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) method, as shown in the following example:


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

注釈

メソッドSequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)は、2つのソースシーケンスを並列で列挙し、対応する要素を、 DefaultTSource既定の等値比較子を使用して比較します。The SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) method enumerates the two source sequences in parallel and compares corresponding elements by using the default equality comparer for TSource, Default.

既定の等値比較Default子は、型の値を比較するために使用されます。The default equality comparer, Default, is used to compare values of the types. カスタムデータ型を比較するには、 Equals GetHashCodeメソッドとメソッドIEquatable<T>をオーバーライドし、必要に応じてカスタム型のジェネリックインターフェイスを実装する必要があります。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. 詳細については、Default プロパティを参照してください。For more information, see the Default property.

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

指定された IEqualityComparer<T> を使用して要素を比較することで、2 つのシーケンスが等しいかどうかを判断します。Determines whether two sequences are equal by comparing their elements by using a specified IEqualityComparer<T>.

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);
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

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>

second と比較する IEnumerable<T>An IEnumerable<T> to compare to second.

second
IEnumerable<TSource>

最初のシーケンスと比較する IEnumerable<T>An IEnumerable<T> to compare to the first sequence.

comparer
IEqualityComparer<TSource>

要素の比較に使用する IEqualityComparer<T>An IEqualityComparer<T> to use to compare elements.

戻り値

2 つのソース シーケンスが同じ長さで、comparer に従ってそれらに対応する要素が等しい場合は true。それ以外の場合は falsetrue if the two source sequences are of equal length and their corresponding elements compare equal according to comparer; otherwise, false.

例外

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

次の例は、 SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)メソッド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。The following example shows how to implement an equality comparer that can be used in the SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>) 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

この比較子を実装した後、次のProduct例に示すSequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)ように、メソッドでオブジェクトのシーケンスを使用できます。After you implement this comparer, you can use sequences of Product objects in the SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>) method, as shown in the following example:


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

注釈

メソッドSequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)は、2つのソースシーケンスを並列で列挙し、指定さIEqualityComparer<T>れたを使用して対応する要素を比較します。The SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>) method enumerates the two source sequences in parallel and compares corresponding elements by using the specified IEqualityComparer<T>. Defaultcomparernull場合は、既定の等値比較子 () を使用して要素を比較します。If comparer is null, the default equality comparer, Default, is used to compare elements.

適用対象