How to determine if there are two or one number at the beginning of my line?

Question

How to determine which number (with an arbitrary number of digits) is at the beginning of a line?

Some possible lines:

1123|http://example.com
2|daas

Which should return 1123 and 2.

Answer 1

You can use LINQ:

string s = "35|...";

int result = int.Parse(new string(s.TakeWhile(char.IsDigit).ToArray()));

or (if the number always follows |) good string manipulation:

string s = "35|...";

int result = int.Parse(s.Substring(0, s.IndexOf('|')));

Answer 2

Use regex:

using System.Text.RegularExpressions;

str = "35|http:\/\/v10.lscache3.c.youtube.com\/videoplayback...";

Regex r = new Regex(@"^[0-9]{1,2}");
Match m = r.Match(str);    
if(m.Success) {
    Console.WriteLine("Matched: " + m.Value);
} else {
    Console.WriteLine("No match");
}

will write 1-2 digits at the beginning of the line.

Answer 3

, 2 :

string str = "35|http:\/\/v10.lscache3.c.youtube.com\/videoplayback?...";
int result;
if (!int.TryParse(str.Substring(0, 2), out result)) {
    int.TryParse(str.Substring(0, 1), out result)
}
// use the number

, , .indexOf() dtb. - , .

Answer 4

int.

var s = "a35|...";
short result = 0;
bool isNum = Int16.TryParse(s.Substring(0, 2), out result);