title: validate comma separated list using regex
body: <p>I want to validate that the user has entered a comma separated list of words only using regex, will this work/is there a better way:</p>
  
  <pre><code> $match = "#^([^0-9 A-z])(,\s|$))+$#";
  </code></pre>
  
  <p>This is not for parsing, as I will use explode for that, it is merely to validate that the user has correctly understood that values should be separated with commas.</p>