check whether a List contains an element in another List using LINQ

Question

How do I check whether a List contains an element that exists in another List using LINQ in C#? I don\'t want to use a for/while loop.

So, if List1 has A, B, C and L

Answer 1

Use Enumerable.Any Method:

List<string> l1 = new List<string> { "1", "2" };
List<string> l2 = new List<string> { "1", "3" };
var result = l2.Any(s => l1.Contains(s));

I'd say the Intersect method (see answer by dasblinkenlight) + Any must work better than Contains + Any. It is definetely better to use Any than Count.

Answer 2

Try this:

List<string> a = ...
List<string> b = ...
var inComon = a.Intersect(b).Any();