Find and extract a number from a string

Question

I have a requirement to find and extract a number contained within a string.

For example, from these strings:

string test = \"1 test\"
string test1 =         


        

Answer 1

go through the string and use Char.IsDigit

string a = "str123";
string b = string.Empty;
int val;

for (int i=0; i< a.Length; i++)
{
    if (Char.IsDigit(a[i]))
        b += a[i];
}

if (b.Length>0)
    val = int.Parse(b);