Enumerable::Except<TSource> Method (IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)

Produces the set difference of two sequences by using the specified IEqualityComparer<T> to compare values.

Namespace:  System.Linq
Assembly:  System.Core (in System.Core.dll)

[ExtensionAttribute]
public:
generic<typename TSource>
static IEnumerable<TSource>^ Except(
	IEnumerable<TSource>^ first, 
	IEnumerable<TSource>^ second, 
	IEqualityComparer<TSource>^ comparer
)

Type Parameters

TSource

The type of the elements of the input sequences.

Parameters

first
Type: System.Collections.Generic::IEnumerable<TSource>

An IEnumerable<T> whose elements that are not also in second will be returned.

second
Type: System.Collections.Generic::IEnumerable<TSource>

An IEnumerable<T> whose elements that also occur in the first sequence will cause those elements to be removed from the returned sequence.

comparer
Type: System.Collections.Generic::IEqualityComparer<TSource>

An IEqualityComparer<T> to compare values.

Return Value

Type: System.Collections.Generic::IEnumerable<TSource>
A sequence that contains the set difference of the elements of two sequences.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable<TSource>. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).

ExceptionCondition
ArgumentNullException

first or second is nullptr.

If comparer is nullptr, the default equality comparer, Default, is used to compare values.

The following example shows how to implement an equality comparer that can be used in the Except method.

No code example is currently available or this language may not be supported.

After you implement this comparer, you can use sequences of Product objects in the Except method, as shown in the following example.

No code example is currently available or this language may not be supported.

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0

Portable Class Library

Supported in: Portable Class Library

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
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