title: Remove the text outside the brackets
body: <p>i.e.</p>
  
  <pre><code>$text = 'remove this text (keep this text and 123)';
  
  echo preg_replace('', '', $text);
  </code></pre>
  
  <p>It should output:</p>
  
  <pre><code>(keep this text and 123)
  </code></pre>