Match a regular expression

Question

Im trying to get the regex expression that will match 15 characters excluding an optional hyphen. so that means the string could be 15 characters including a hyphen.

Answer 1

You could just filter out the hyphens before doing the test:

string value = "FU48WYE8U878HW7";

if (Regex.IsMatch(value.Replace("-", ""), @"^[\w]{15}$")) {
    Console.WriteLine("Matches");
}