Question

string dosage = "2/3/5 mg";
string[] dosageStringArray = dosage.Split('/');
int[] dosageIntArray = null;
for (int i = 0; i <= dosageStringArray.Length; i++) 
{
    if (i == dosageStringArray.Length)
    {
        string[] lastDigit = dosageStringArray[i].Split(' ');
        dosageIntArray[i] = Common.Utility.ConvertToInt(lastDigit[0]);
    }
    else
    {
        dosageIntArray[i] = Common.Utility.ConvertToInt(dosageStringArray[i]);
    }
}

I am getting the exception on this line: dosageIntArray[i] = Common.Utility.ConvertToInt(dosageStringArray[i]);
I am unable to resolve this issue. Not getting where the problem is. But this line int[] dosageIntArray = null; is looking suspicious.

Exception: Object reference not set to an instance of an object.

Answer 1

The biggest problem with your solution is not the missing array declaration, but rather how
you’d parse the following code:

string dosage = "2/13/5 mg";

Since your problem is surely domain specific, this may not arise, but some variation of two digits representing same integer.

The following solution splits the string on forward slash, then removes any non-digits from the substrings before converting them to integers.

Regex digitsOnly = new Regex(@"[^\d]");   
var array = dosage.Split('/')
                  .Select(num => int.Parse(digitsOnly.Replace(num, string.Empty)))
                  .ToArray();

Or whatever that looks like with the cuddly Linq synthax.