title: Multiple Formats with PHP DateTime::createFromFormat()
body: <p>Let's say the user can submit their time as strings in one of multiple formats.  Is there any way in <code>DateTime::createFromFormat()</code> to specify multiple formats to parse. </p>
  
  <p>Right now I notice if you specify a format, any missing elements cause an error.</p>
  
  <p>For example, lets say I'm accepting both <code>1h22m34s</code> and a <code>21m22s</code> as valid time strings (the second implies <code>00h</code>, but doesn't require it).</p>
  
  <p>The following will throw an error on the second string when seen:</p>
  
  <pre><code>   $mytime = `21m22s`;
     echo DateTime::createFromFormat('H\hi\ms\s',$mytime)-&gt;format('H:i:s');
  </code></pre>
  
  <p>How can I work to allow it to parse multiple formats?</p>
  
  <p>Or is there another, non-hack way to work with multiple formats?</p>