What is LINQ Union method in C#?

What is LINQ Union method in C#?

The LINQ Union Method in C# is used to combine the multiple data sources into one data source by removing the duplicate elements. There are two overloaded versions available for the LINQ Union Method as shown below. Let us understand this with an example.

Why iequalitycomparer can’t compare multiple values in a single column?

Because it doesn’t know howto compare, there is no issue while we have a single column value in the collection but here we have more than one column so that it can’t compare, so shall we specify the fields to compare? We can overcome this issue by using IEqualityComparer.

What is the use of equality comparer in Union?

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

How to get the set union of two IEnumerable?

Produces the set union of two sequences by using a specified IEqualityComparer . The type of the elements of the input sequences. An IEnumerable whose distinct elements form the first set for the union. An IEnumerable whose distinct elements form the second set for the union.

Why Union extend method does not perform unique operation with large collections?

In the above result you can see, there are the duplicate values, the union extend method doesn’t perform its unique operation with large collections because it doesn’t know which field to compare, so we need to specify which field to compare. To overcome this problem “IEqualityComparer” interface

What is the use of Union in Python?

In above result you can see the elements are unique because union removed the repeated/duplicate elements from both collections/ list. Now we got a clear picture about union, the union is used to return the distinct elements from both collections.