Question

Say I’ve got two lists:

List<string>foo=new List<string>();
List<string>bar=new List<string>();

I want to merge these two lists and return another list with only the duplicates in the both.

So if I have:

//pseudocode
foo={"baz","lemons","somethingelse"}
bar={"what","another","baz","somethingelse","kitten"}

I want it to return a new List:

//pseudocode
dupes={"baz","somethingelse"}

I think using LINQ will be the best shot. However, I haven’t quite figured that since I have poor LINQ experience.

Answer 1

Intersect is what you want which is part of LINQ.

dupes = foo.Intersect(bar).ToList();

Ensure you have the System.Linq namespace referenced in your file.