how to select elements that not intersec?

Question

If I have two list and I want the elements that are common in both lists, I can use this code:

var listC = listA.Intersect(listB);

However, If I want the elements that are not common? And without duplicates? is possible with intersect?

Thanks.

score 3 · Answer 1 · answered Jun 09 '13 at 09:04

3

Neither answer so far will include items from listB that aren't in listA. To get any item that is in either list, but is not in both lists:

listA.Union(listB).Except(listA.Intersect(listB));

answered Jun 09 '13 at 09:04

Kent Boogaart

Alternatively, you can also do `listA.Except(listB).Union(listB.Except(listA))` – Robert McKee Jun 09 '13 at 17:08
+1, it's a better answer than mine. – It'sNotALie. Jun 10 '13 at 08:23

score 1 · Accepted Answer · answered Jun 09 '13 at 09:02

1

Yep, that's possible. It's called Enumerable.Except.

Use this:

var result = listA.Except(listB); //maybe a .ToList() at the end,
//or passing an IEqualityComparer<T> if you want a different equality comparison.

answered Jun 09 '13 at 09:02

It'sNotALie.

score 1 · Answer 3 · answered Jun 09 '13 at 22:57

1

Most efficient:

var set = new HashSet<T>(listA);
set.SymmetricExceptWith(listB);

answered Jun 09 '13 at 22:57

lisp

3 Answers3