title: Convert Wordpress user registered date / time into unix timestamp
body: <p>I need to convert a <code>user_registered</code> date from wordpress into a UNIX timestamp.</p>
  
  <p>The output of the below returns</p>
  
  <pre><code>$get_users = get_users( array( 'blog_id' =&gt; get_current_blog_id() ) );
  $user_id = $get_users[0]-&gt;ID;
  $user_info = get_userdata($user_id);
  $user_registered_date = $user_info-&gt;user_registered;
  </code></pre>
  
  <p><code>$user_registered_date</code> returns <code>2017-01-17 15:43:18</code></p>
  
  <p>I need to convert the date into a UNIX timestamp. How would I go about this?</p>
  
  <p>Thanks</p>