StepUp StepUp - 7 months ago 50
C# Question

Regular expression for signs which depends alphanumeric

The row should be:

  • contains alphanumeric, dot sign
    and minus sign
    , spaces, underscore, slash

  • if there is no alphanumeric, then regular expression should return false

I've written the following

string pattern = @"^[a-zA-Z0-9._\+\-\/\s]+$";

and the second condition is not satisfied:

string s1 = "."; // or dot, space, underscore, slash

// Compare a string against the regular expression
var isOK = new Regex(pattern).IsMatch(s1); // true, but I would like to be false

Could you tell me the right way to create a

ndn ndn

Firstly, there is a character set, which contains [a-zA-Z0-9_] - \w. Secondly, you don't need to escape the + inside character sets.

As for the actual solution, you can just use a positive lookahead to guarantee at least one such character exists somewhere in the string after some number of characters (.*):