Question

I have a generic GetMinimum method. It accepts array of IComparable type (so it may be string[] or double[]). in the case of double[] how can I implement this method to ignore the double.NaN values? (I’m looking for good practices)

when I pass this array

double[] inputArray = { double.NaN, double.NegativeInfinity, -2.3, 3 };

it returns the double.NaN!

public T GetMinimum<T>(T[] array) where T : IComparable<T>
{
    T result = array[0];
    foreach (T item in array)
    {
        if (result.CompareTo(item) > 0)
        {
            result = item;
        }
    }
    return result;
}

Answer 1

Since both NaN < x and NaN > x will always be false, asking for the minimum of a collection that can contain NaN is simply not defined. It is like dividing by zero: there is no valid answer.

So the logical approach would be to pre-filter the values. That will not be generic but that should be OK.

 var results = inputArray.EliminateNaN().GetMinimum();

Separation of concerns: the filtering should not be the responsibility (and burden) of GetMinimum().