title: php 8.1 - explode(): Passing null to parameter #2 ($string) of type string is deprecated
body: <p>Coming across some deprecated errors with 8.1 I want to address.</p>
  <p><code>PHP Deprecated:  explode(): Passing null to parameter #2 ($string) of type string is deprecated in...</code></p>
  <pre><code>//explode uids into an array
  $comp_uids = explode(',', $result['comp_uids']);
  </code></pre>
  <p>$result['comp_uids'] in this case is empty which is why the null error shows.  I'm not sure why they are deprecating this ability, but what is the recommended change to avoid this?  I'm seeing similar with <code>strlen(): Passing null to parameter #1 ($string) of type string is deprecated</code> and a few others using 8.1.</p>