Distinct list of lists, where lists contains same values but in different order

Question

I got a list:

var list = new List>();

which could contain

list[0] = {1, 2, 3, 4}
lis         


        

Answer 1

Here's the euqality comparer Jon Skeet is talking about (his advice regarding working with HashSets to begin with is also spot on, of course):

    public class EnumerableComparer : IEqualityComparer> 
                                          where T : IComparable
    {
        public bool Equals(IEnumerable first, IEnumerable second)
        {
            if (first == second)
                return true;
            if ((first == null) || (second == null))
                return false;

            return new HashSet(first).SetEquals(second);
        }

        public int GetHashCode(IEnumerable enumerable)
        {
            return enumerable.OrderBy(x => x)
              .Aggregate(17, (current, val) => current*23 + val.GetHashCode());
        }
    }

So you'd do something like:

list.Distinct(new EnumerableComparer());

If the elements are not guaranteed to be unique - Use the IEqualityComparer I posted here: Comparing two collections for equality irrespective of the order of items in them

(In previous edits, I mistakingly posted an IEqulityComparer that compares between two lists of lists - could be very useful when dealing with partitions, but that's a different topic)