Queryable.SequenceEqual Method

Definition

Namespace:

System.Linq

Assemblies:

netstandard.dll, System.Linq.Queryable.dll

Determines whether two sequences are equal.

Overloads

SequenceEqual<TSource>(IQueryable<TSource>, IEnumerable<TSource>)	Determines whether two sequences are equal by using the default equality comparer to compare elements.
SequenceEqual<TSource>(IQueryable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)	Determines whether two sequences are equal by using a specified IEqualityComparer<T> to compare elements.

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

Source:

Queryable.cs

Determines whether two sequences are equal by using the default equality comparer to compare elements.

C#

public static bool SequenceEqual<TSource>(this System.Linq.IQueryable<TSource> source1, System.Collections.Generic.IEnumerable<TSource> source2);

Type Parameters

TSource

The type of the elements of the input sequences.

Parameters

source1

IQueryable<TSource>

An IQueryable<T> whose elements to compare to those of source2.

source2

IEnumerable<TSource>

An IEnumerable<T> whose elements to compare to those of the first sequence.

Returns

Boolean

true if the two source sequences are of equal length and their corresponding elements compare equal; otherwise, false.

Exceptions

ArgumentNullException

source1 or source2 is null.

Examples

The following code example demonstrates how to use SequenceEqual<TSource>(IQueryable<TSource>, IEnumerable<TSource>) to determine whether two sequences are equal. In this example the sequences are equal.

C#

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 };

    // Determine if the lists are equal.
    bool equal = pets1.AsQueryable().SequenceEqual(pets2);

    Console.WriteLine(
        "The lists {0} equal.",
        equal ? "are" : "are not");
}

/*
    This code produces the following output:

    The lists are equal.
*/

The following code example compares two sequences that are not equal.

C#

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 }
    };

    // Determine if the lists are equal.
    bool equal = pets1.AsQueryable().SequenceEqual(pets2);

    Console.WriteLine("The lists {0} equal.", equal ? "are" : "are NOT");
}

/*
    This code produces the following output:

    The lists are NOT equal.
*/

Remarks

The SequenceEqual<TSource>(IQueryable<TSource>, IEnumerable<TSource>) method generates a MethodCallExpression that represents calling SequenceEqual<TSource>(IQueryable<TSource>, IEnumerable<TSource>) itself as a constructed generic method. It then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source1 parameter.

The query behavior that occurs as a result of executing an expression tree that represents calling SequenceEqual<TSource>(IQueryable<TSource>, IEnumerable<TSource>) depends on the implementation of the type of the source1 parameter. The expected behavior is that it determines if the two source sequences are equal.

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

Source:

Queryable.cs

Determines whether two sequences are equal by using a specified IEqualityComparer<T> to compare elements.

C#

public static bool SequenceEqual<TSource>(this System.Linq.IQueryable<TSource> source1, System.Collections.Generic.IEnumerable<TSource> source2, System.Collections.Generic.IEqualityComparer<TSource>? comparer);

Type Parameters

TSource

The type of the elements of the input sequences.

Parameters

source1

IQueryable<TSource>

An IQueryable<T> whose elements to compare to those of source2.

source2

IEnumerable<TSource>

An IEnumerable<T> whose elements to compare to those of the first sequence.

comparer

IEqualityComparer<TSource>

An IEqualityComparer<T> to use to compare elements.

Returns

Boolean

true if the two source sequences are of equal length and their corresponding elements compare equal; otherwise, false.

Exceptions

ArgumentNullException

source1 or source2 is null.

Remarks

The SequenceEqual<TSource>(IQueryable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>) method generates a MethodCallExpression that represents calling SequenceEqual<TSource>(IQueryable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>) itself as a constructed generic method. It then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source1 parameter.

The query behavior that occurs as a result of executing an expression tree that represents calling SequenceEqual<TSource>(IQueryable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>) depends on the implementation of the type of the source1 parameter. The expected behavior is that it determines if the two source sequences are equal by using comparer to compare elements.