Split numeric part from alphanumeric string using C#

Question

I have alphanumeric string list. For example:

1A
2B
7K
10A

I want to get only the numeric part and then compare them, if it is less than 10 I need not to add it in another list. What I want to know the regex to split the numeric part from the string. Any help. What I have done till now is:

 if (x == y) // also handles null
            return 0;
        if (x == null)
            return -1;
        if (y == null)
            return +1;

        int ix = 0;
        int iy = 0;
        while (ix < x.Length && iy < y.Length)
        {
            if (Char.IsDigit(x[ix]) && Char.IsDigit(y[iy]))
            {
                // We found numbers, so grab both numbers
                int ix1 = ix++;
                int iy1 = iy++;
                while (ix < x.Length && Char.IsDigit(x[ix]))
                    ix++;
                while (iy < y.Length && Char.IsDigit(y[iy]))
                    iy++;
                string numberFromX = x.Substring(ix1, ix - ix1);
                string numberFromY = y.Substring(iy1, iy - iy1);

                // Pad them with 0's to have the same length
                int maxLength = Math.Max(
                    numberFromX.Length,
                    numberFromY.Length);
                numberFromX = numberFromX.PadLeft(maxLength, '0');
                numberFromY = numberFromY.PadLeft(maxLength, '0');

                int comparison = _CultureInfo
                    .CompareInfo.Compare(numberFromX, numberFromY);
                if (comparison != 0)
                    return comparison;
            }
            else
            {
                int comparison = _CultureInfo
                    .CompareInfo.Compare(x, ix, 1, y, iy, 1);
                if (comparison != 0)
                    return comparison;
                ix++;
                iy++;
            }
        }

But I don't want to be so complex in my approach. So I need a regex to split.

Answer 1

Try IsDigit method of char

var number = int.Parse(new string(someString.Where(char.IsDigit).ToArray()));
if(number<10)
{
   someList.Add(number);
}

using All and IsDigit you can take only numeric part of the string, then parse it to int and compare :) There is no need to use Regexes

Answer 2

You can use the code below to split an input string and get the result of number group and alpha group. If one group is not there, the result will be empty string.

string input = "10AAA";
Match m = Regex.Match(input, @"(\d*)(\D*)");

string number = m.Groups[1].Value;
string alpha = m.Groups[2].Value;

Answer 3

you can try it with this one:

  string txt="10A";
  string re1="(\\d+)";  // Integer Number 1

  Regex r = new Regex(re1);
  Match m = r.Match(txt);

Answer 4

Are you trying to do this?

int num;
string stringWithNumbers = "10a";
if (int.TryParse(Regex.Replace(stringWithNumbers, @"[^\d]", ""), out num))
{
    //The number is stored in the "num" variable, which would be 10 in this case.
    if (num >= 10)
    {
        //Do something
    }

}
else
{
    //Nothing numeric i the string
}