Remove items from one list in another

Question

I'm trying to figure out how to traverse a generic list of items that I want to remove from another list of items.

So let's say I have this as a hypothetical example

List<car> list1 = GetTheList(); List<car> list2 = GetSomeOtherList(); 

I want to traverse list1 with a foreach and remove each item in List1 which is also contained in List2.

I'm not quite sure how to go about that as foreach is not index based.

Answer 1

You can use Except:

List<car> list1 = GetTheList(); List<car> list2 = GetSomeOtherList(); List<car> result = list2.Except(list1).ToList(); 

You probably don't even need those temporary variables:

List<car> result = GetSomeOtherList().Except(GetTheList()).ToList(); 

Note that Except does not modify either list - it creates a new list with the result.

Answer 2

You don't need an index, as the List<T> class allows you to remove items by value rather than index by using the Remove function.

foreach(car item in list1) list2.Remove(item);