How can I add elements from one collection that do not exist in a second collection to a third collection?

Question

I have 3 generic lists:

List<string> input
List<string> compareTo
List<string> results

I'd like to take the list of input and compare each value to the compare list, and if it doesn't exist add it to the results list.

Answer 1

你有什么理由不能只使用LINQ吗？

List<string> results = input.Except(compareTo).ToList();

Answer 2

compareTo.ForEach( x => {

    if(!input.Contains(x))results.Add(x); 


    });