Enumerable.SequenceEqual<TSource> Method (IEnumerable<TSource>, IEnumerable<TSource>)

Type Parameters

• TSource
  The type of the elements of the input sequences.

Parameters

• first
  Type: System.Collections.Generic.IEnumerable<TSource>
  An IEnumerable<T> to compare to second.

• second
  Type: System.Collections.Generic.IEnumerable<TSource>
  An IEnumerable<T> to compare to the first sequence.

Return Value

Type: System.Boolean
true 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.

   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")
      outputBlock.Text &= "The lists " & text & " equal." & vbCrLf

   End Sub

   ' This code produces the following output:
   '
   ' The lists 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);

         outputBlock.Text += String.Format(
             "The lists {0} equal.",
             equal ? "are" : "are not") + "\n";
      }

      /*
       This code produces the following output:

       The lists are 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")
      outputBlock.Text &= "The lists " & text & " equal." & vbCrLf

      ' This code produces the following output:
      '
      ' The lists are not 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);

         outputBlock.Text += String.Format("The lists {0} equal.", equal ? "are" : "are not") + "\n";
      }

      /*
       This code produces the following output:

       The lists are not equal.
      */

Public Class Product
    Implements IEquatable(Of Product)

    Public Property Name As String
    Public Property Code As Integer

    Public Function Equals1(
        ByVal other As Product
        ) As Boolean Implements IEquatable(Of Product).Equals

        ' Check whether the compared object is null.
        If other Is Nothing Then Return False

        ' Check whether the compared object references the same data.
        If Me Is Other Then Return True

        ' Check whether the products' properties are equal.
        Return Code.Equals(other.Code) AndAlso Name.Equals(other.Name)
    End Function

    Public Overrides Function GetHashCode() As Integer

        ' Get hash code for the Name field if it is not null.
        Dim hashProductName = If(Name Is Nothing, 0, Name.GetHashCode())

        ' Get hash code for the Code field.
        Dim hashProductCode = Code.GetHashCode()

        ' Calculate the hash code for the product.
        Return hashProductName Xor hashProductCode
    End Function
End Class

public class Product : IEquatable<Product>
{
    public string Name { get; set; }
    public int Code { get; set; }

    public bool Equals(Product other)
    {

        //Check whether the compared object is null.
        if (Object.ReferenceEquals(other, null)) return false;

        //Check whether the compared object references the same data.
        if (Object.ReferenceEquals(this, other)) return true;

        //Check whether the products' properties are equal.
        return Code.Equals(other.Code) && Name.Equals(other.Name);
    }

    // If Equals() returns true for a pair of objects 
    // then GetHashCode() must return the same value for these objects.

    public override int GetHashCode()
    {

        //Get hash code for the Name field if it is not null.
        int hashProductName = Name == null ? 0 : Name.GetHashCode();

        //Get hash code for the Code field.
        int hashProductCode = Code.GetHashCode();

        //Calculate the hash code for the product.
        return hashProductName ^ hashProductCode;
    }
}

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)

outputBlock.Text &= "Equal? " & equalAB & vbCrLf

' This code produces the following output:

' Equal? True

        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);

        outputBlock.Text += "Equal? " + equalAB + "\n";

        /*
            This code produces the following output:

            Equal? True
        */