Question

Looking for either a solution, some ideas or being point in the right direction on how to resolve a problem.

Basically, I have to figure out if a string value is in between a Low and High string value. However, the values are in a format which String.Compare will not work. But, a human can easily figure out.

For example, one of my ranges is Low: A7, High A12. A8 fits in between those values but String.Compare says it does not. A13 would not fit between the values.

Other examples of Low and High values are:

Low Value – High Value

1A1 – 1A12

25W00 – 25W050

42W1 – 42W296

W232N0002 – W232N000598

In the above examples 1A2 would fit between the Low High Value of 1A1 and 1A12, but 1A100 would not.

Any ideas on how to resolve this? I know this had to have been encountered before.

Answer 1

This could use some optimization, but it’s a proof of concept.
Just convert the letters to numerical values and compare the results:

private bool ValueIsBetween(string value, string lowValue, string highValue)
{
    long low = long.Parse(ConvertToNumber(lowValue));
    long high = long.Parse(ConvertToNumber(highValue));
    long val = long.Parse(ConvertToNumber(value));
    return val > low && val < high;
}

private string ConvertToNumber(string value)
{
    value = value.ToUpper();
    value = value.Replace("A", "0");
    value = value.Replace("B", "1");
    value = value.Replace("C", "2");
    value = value.Replace("D", "3");
    value = value.Replace("E", "4");
    value = value.Replace("F", "5");
    value = value.Replace("G", "6");
    value = value.Replace("H", "7");
    value = value.Replace("I", "8");
    value = value.Replace("J", "9");
    value = value.Replace("K", "10");
    value = value.Replace("L", "11");
    value = value.Replace("M", "12");
    value = value.Replace("N", "13");
    value = value.Replace("O", "14");
    value = value.Replace("P", "15");
    value = value.Replace("Q", "16");
    value = value.Replace("R", "17");
    value = value.Replace("S", "18");
    value = value.Replace("T", "19");
    value = value.Replace("U", "20");
    value = value.Replace("V", "21");
    value = value.Replace("W", "22");
    value = value.Replace("X", "23");
    value = value.Replace("Y", "24");
    value = value.Replace("Z", "25");

    return value;
}

---

Results:

ValueIsBetween("1A2", "1A1", "1A12");

true

ValueIsBetween("1A100", "1A1", "1A12");

false

ValueIsBetween("43W4", "42W1", "44W3");

true

Edit:
Try this improved algorithm instead:

private bool ValueIsBetween(string value, string lowValue, string highValue)
{
    return !ValueIsLessThan(value, lowValue) && ValueIsLessThan(value, highValue);
}

private bool ValueIsLessThan(string value, string compareTo)
{
    var matches = Regex.Matches(value, "[0-9]+|[a-zA-Z]+");
    var matchesB = Regex.Matches(compareTo, "[0-9]+|[a-zA-Z]+");

    var count = matches.Count < matchesB.Count ? matches.Count : matchesB.Count;

    for (int i = 0; i < count; i++)
    {
        long val;
        long val2;
        if (long.TryParse(matches[i].Value, out val))
        {
            if (long.TryParse(matchesB[i].Value, out val2))
            {
                if (val > val2) return false;
                if (val < val2) return true;
            }
            else
            {
                return false;
            }
        }
        else
        {
            if (matches[i].Value.CompareTo(matchesB[i].Value) > 0 ) return false;
            if (matches[i].Value.CompareTo(matchesB[i].Value) < 0 ) return true;
        }
    }

    return true;
}

---

Results:

ValueIsBetween("B431Z543", "A0", "Z9");

true

ValueIsBetween("4B31Z543", "A0", "Z9");

false

ValueIsBetween("1A2", "1A1", "1A12");

true

ValueIsBetween("1A100", "1A1", "1A12");

false

ValueIsBetween("43W4", "42W1", "44W3");

true

ValueIsBetween("W5", "CC4", "CC6");

false

ValueIsBetween("W8B4", "W5C3", "W7C3");

false

ValueIsBetween("W5C4", "W5C3", "C7W3"); 

false