title: Regex to enforce alpha-numeric but allow apostrophes and hyphens?
body: <p>How would I alter this function so that it allows single apostrophe's and hyphens:</p>
  
  <pre><code>function sanitize_string($s) {
      $result = preg_replace("/[^a-zA-Z0-9]+/", " ", html_entity_decode($s, ENT_QUOTES));
      return $result;
  }
  </code></pre>