title: PHP Replace second occurence of ? with an &
body: <p>I have few strings, if the string is as below </p>
  
  <pre><code>$string ="w?w+f=w?wefwef?blahblah";
  
  $desiredString ="w?w+f=w&amp;wefwef?blahblah";
  </code></pre>
  
  <p>If this format, I am trying to replace second ? to &amp; else do nothing. </p>
  
  <p>I've tried regex and preg_match but no luck.</p>