title: php array difference
body: <p>I'm trying to find the difference in 2 arrays.</p>
  
  <pre><code>$inven_old = array(1,2,3,4); 
  $inven_new = array(1,2,3,4,5); 
  $result = array_diff($inven_old, $inven_new); 
  print_r($result);
  </code></pre>
  
  <p>Why is the outcome nothing? </p>
  
  <p>Shouldn't it be "5" ? </p>
  
  <p>If not, how can I do what I'm trying to do?</p>