title: How to pick a group of elements in an array?
body: <p>I have a big array with <strong>some of the elements are arrays</strong>.</p>
  
  <p><strong>Some of the elements and sub-elements</strong> are , Let's say, "forbbidden names".</p>
  
  <p>Now, if I input a name that is one of the forbbidden names, I want to make it invalid.</p>
  
  <p>My question is-- how to get an array of "forbbidden names"?</p>