Get differences between two list

Question

I have a 2 lists of an object type:

List<MyClass> list1;

List<MyClass> list2;

What is the best way (performance and clean code) to extract differences in data between these two List?
I mean get objects that is added, deleted, or changed (and the change)?

Solution 1

Try Except with Union, but you'll need to do it for both in order to find differences in both.

var exceptions = list1.Except(list2).Union(list2.Except(list1)).ToList();

OR as a Linq alternative, there could be a much faster approach: HashSet.SymmetricExceptWith():

var exceptions = new HashSet(list1);

exceptions.SymmetricExceptWith(list2);

Solution 2

IEnumerable<string> differenceQuery = list1.Except(list2);

http://msdn.microsoft.com/en-us/library/bb397894.aspx

Comments

[mattytommo]

That won't give you the items only in list 2 :)

[Darren]

@MitchWheat - why does it matter about the time I posted the answer?