title: regular expression ".*[^a-zA-Z0-9_].*"
body: <p>As I am trying to read more about regular expressions in C#, I just want to make sure of my conclusion that I made.
  for the following expression ".*[^a-zA-Z0-9_].* ", the  " .* " at the beginning and end are useless, is that right ? because as I understood, that ".*" means zero or more occurrence of any character, but being followed by "[^a-zA-Z0-9_]" which means any character other than any combination of letters and digits case insensitive, makes ".*" useless to be added before and after "[^a-zA-Z0-9_]", is that right ?</p>
  
  <p>Here is the code I am using to check if the expressions matches</p>
  
  <pre><code>// Here we call Regex.Match.
  Match match = Regex.Match("anytest#", ".*[^a-z A-Z0-9_].*");
  //Match match = Regex.Match("anytest#", "[^a-z A-Z0-9_]");
  
  // Here we check the Match instance.
  if (match.Success)
      Console.WriteLine("error");
  else
      Console.WriteLine("no error");
  </code></pre>