C# Find a matching string by regex

Question

I want to find out, whether my string contains a text like #1, #a, #abc, #123, #abc123dsds and so on... (\'#\' character with one or more characters (digits and letters).

Answer 1

Or without regex, you can use a combination of StartsWith, Enumerable.Any and char.IsLetterOrDigit methods like;

var s = "#abc123dsds+";
var matches = s.Length > 1 && s.StartsWith("#") && s.Substring(1).All(char.IsLetterOrDigit);