Question

I have an array of float elements and I’m trying to remove elements that are close to each other.
I.e. if there are two elements less than 0.4 apart (e.g. 15.1 and 15.3), I want to remove the second one. The 0.4 should be the input parameter for the algorithm.

The array is already sorted in a specific order (not ascending/descending) and I need to preserve that order.

Answer 1

I have created an ApproximateFloatComparer class as follows:

public class ApproximateFloatComparer : IComparer<float>
{
    public float Range { get; set; }

    public ApproximateFloatComparer(float range)
    {
        this.Range = range;
    }

    public int Compare(float x, float y)
    {
        if (x - this.Range < y && x + this.Range > y)
            return 0;
        else return x.CompareTo(y);
    }
}

Then create a method to deduplicate:

public static List<float> Deduplicate(List<float> floats, float range)
{
    var dedup = new List<float>();
    var comparer = new ApproximateFloatComparer(range);
    foreach (var @float in floats)
        if (!dedup.Any(f => comparer.Compare(f, @float) == 0))
            dedup.Add(@float);
    return dedup;
}

Then combine it all:

var floats = new List<float>() { 5, 8, 2, 13, 6, 9, 4, 3, 2.1f, 8.6f, 2.2f };
floats = Deduplicate(floats, 0.4f);