My task is to check which of the elements of a column in one csv are not included in the elements of a column in the other csv. There is a country column in both csv and the task is to check which countries are not in the secong csv but are in the first csv.

I guess I have to solve it with Lists after I read the strings from the two csv. But I dont know how to check which items in the first list are not in the other list and then put it to a third list.