Delete duplicates in a List of int arrays

Question

having a List of int arrays like:

List intArrList = new List();
intArrList.Add(new int[3] { 0, 0, 0 });
intArrList.Add(new int[5] {         


        

Answer 1

Using MoreLINQ this can be very simple with DistinctBy.

var result = intArrList.DistinctBy(x => string.Join(",", x));

Similar to the GroupBy answer if you want distinction to be irrespective of order just order in the join.

var result = intArrList.DistinctBy(x => string.Join(",", x.OrderBy(y => y)));

EDIT: This is how it's implemented

public static IEnumerable DistinctBy(this IEnumerable source,
            Func keySelector, IEqualityComparer comparer)
        {
            if (source == null) throw new ArgumentNullException(nameof(source));
            if (keySelector == null) throw new ArgumentNullException(nameof(keySelector));

            return _(); IEnumerable _()
            {
                var knownKeys = new HashSet(comparer);
                foreach (var element in source)
                {
                    if (knownKeys.Add(keySelector(element)))
                        yield return element;
                }
            }
        }

So you if you don't need MoreLINQ for anything else you can just use a method like this:

private static IEnumerable GetUniqueArrays(IEnumerable source)
    {
        var knownKeys = new HashSet();
        foreach (var element in source)
        {
            if (knownKeys.Add(string.Join(",", element)))
                yield return element;
        }
    }