title: Regex - why empty parenthesis?
body: <p>I have a regex to update and there is an empty parenthesis in it. And i wondering : what is the purpose ? I don't find something about it.</p>
  
  <p>The regex : </p>
  
  <pre><code>(DE)()([0-9]{1,12})
  </code></pre>
  
  <p>Because, if it is useless, i can remove it.</p>