removing duplications from List<>

Question

I have a list that contains 1200 items,

I need to remove all of the duplicate items in the list that have a certain predicate, my items have the following status on them:

"not flat", "not covered", "accepted", X, Y, Z

i want to remove all duplicate item from the list that have the same X,Y,Z and have the same Status string

how can I achieve this?

I tried to do this this way:

public class MyEqualityComparer : IEqualityComparer<TcReportPoint3D>
{
    public bool Equals(TcReportPoint3D a, TcReportPoint3D b)
    {
        return a.X == b.X && a.Y == b.Y && a.Z == b.Z && a.Status != b.Status;
    } 

    public int GetHashCode(TcReportPoint3D other)
    {
        return other.X.GetHashCode() * 19 + other.Y.GetHashCode();
    }
}

then:

  //get all distinct values with different status
    var points = reportpoints.Distinct(new MyEqualityComparer()).ToList();

    //remove distinct values from the real least, hoping to remove duplicates.
    foreach (var point in points)
    {
        if (point.Status == TePointStatus.NotCovered
            || point.Status == TePointStatus.OutOfSigma
            || point.Status == TePointStatus.NotFlat)
            reportpoints.Remove(point);
    }

The reason is that i have a list of items that was combined from a logic of two conditions, where the same value will have a different status then the other one.

I want to somehow be able to get the differences out of the list, then remove the duplicates that match the status.

What have you tried so far? What problems are you having? SO is not a write-my-code-for-me site. — Craig W., Jul 30 '15 at 23:07
@Dean when you do List.Remove, you only the first occurrence of the element. This means if you have a List A,A,A and call list.Remove("A"), the remaining list will still contain two "A"s, rights? Ref https://msdn.microsoft.com/en-us/library/cd666k3e(v=vs.110).aspx. After you have a list of distinct points, do you need to revisit the reportPoints list? — KnightFox, Jul 31 '15 at 06:13

CharithJ · Answer 1 · 2015-07-30T23:12:41.927

1

var result = ObjectsWithDuplicates.Select(o => o.StringName).Distinct().ToList();

Or

var result = ObjectsWithDuplicates.GroupBy(o => o.StringName).Select(oo => oo.First()).ToList();

edited Jul 30 '15 at 23:12

answered Jul 30 '15 at 23:07

CharithJ

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score 0 · Answer 2 · answered Jul 30 '15 at 23:13

Here is a simple solution:

List<string> values = new List<string>();
            values.Add("not flat");
            values.Add("not covered");
            values.Add("accepted");
            values.Add("accepted");
            values.Add("not flat");
            values.Add("not flat");
            values.Add("not covered");
            values.Add("not flat");

 List<string> distinctValues = values.Distinct().ToList();

Debug:

removing duplications from List<>

2 Answers2