regex to validate double values

Question

Hi,

I'm trying to come up with a regex to validate a double value. I will admit that I am crap at regex and really should buy a book... Anyway the range is large so here goes:

.01 to 99.99, is the range, with the leading '00' being optional, as is the '.' and the same for the trailing '.00'. So the user could type in 0.1 00.01, 0.11, 1, 1.0 1.00 and these all would be valid.

Thanks, r.

Answer 1

Rather than a RegEx, why not use double's TryParse method?

string[] sa = new string[] { "00.01", "1.00", "xx" };
double d;
bool isValid;
foreach (string s in sa)
{
    isValid = double.TryParse(s, out d) && d >= 0.01d && d <= 99.99d;
    Console.WriteLine("{0}: {1}", s, isValid.ToString());
}

Answer 2

^[0-9]{0,2}\.?[0-9]{0,2}$

you can try it out here: http://www.regular-expressions.info/javascriptexample.html