title: How to validate if a string in PHP only contains letters, single quotes and dash
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/7385420/regex-to-allow-a-z-and">Regex to allow A-Z, - and &#39;</a>  </p>
  </blockquote>
  
  
  
  <p>I have a form that asks for a name, and the name must not contain any numbers but can have a (') or a (-) e.g O'Neal, O-man.</p>
  
  <p>I've already used <code>is_string()</code> but it seems to be strict, does any one of you know how to validate a string that accepts those kinds of values?</p>