Nested For Loops

[BRawn]

Hi,

I'm not an expert at nested for loops and I need help with the following...

I need to extract numeric values from a string and 'discard' any alphabetical characters in the same string. In this case, there will always only be a sequence of 2 numeric strings.

The purpose of this is to append station using racks, should the station need expanding at a later stage. Here's what I have...

string stationCoordinates = stationObjects.StationXY;
                            char[] digits = new char[] { '1', '2', '3', '4', '5', '6', '7', '8', '9', '0' };
                            int rowNumber = 0;
                            int columnNumber = 0;
                            StringBuilder numericString = new StringBuilder();
                            for (int i = 0; i < stationCoordinates.Length; i++)
                            {
                                for (int j = 0; j < stationCoordinates.Length; j++)
                                {
                                    if (char.IsNumber(stationCoordinates[i]))
                                    {
                                        numericString.Append(stationCoordinates[i]);
                                        rowNumber = i;
                                    }
                                }
                            }

What I need help with is setting the 'rowNumber' and 'columnNumber' variables with the values i and j return, respectively. I want i to be 'rowNumber' and j to be 'columnNumer'.

Lets say, for instance, stationCoordina tes' value is "Row33Col44 ", I want the 33 (i) and 44 (j), which value's should be incremented accordingly in my append method. Any ideas?

[Christian Binder]

Ok, I hope I've understood your question: you have lets say stationCoordina tes="Row33Col44 " and you want to set two variables, i and j, e.g. i=33 and j=44.

I'd loop over all chars in stationCoordina tes with foreach(char ch in stationCoordina tes).
Now I'd check ch if it is a valid number. When it is, I'd append it to a temporary string containing digits (as string), otherwise I'd omit it.
When a non-digit is following a digit-character, I'd parse my temporary string and assign it to [i]-variable. Then the same, continuing where I assigned it to i and do the same for j.

string stationCoordinates = "Row33Col44";
string temp = string.Empty;
int i = -1, j = -1;
foreach(char ch in (stationCoordinates + "X")) {
//this +"X" is a hack, that after "44" there's a change to a non-digit character. Doing it better, you can additionally put the part in the following else-section outside the loop ...
  if(char.IsNumber(ch)) {
    temp += ch;
  } else {
    if(!string.IsNullOrEmpty(temp)) {
      //string is containing numbers
      if(i == -1) //i wasn't initialized yet
        i = int.Parse(temp);
      else //i was initialized, assign to j
        j = int.Parse(temp);
      temp = string.Empty; //reset temp string
    }
  }
}