title: Get numbers that does not exist in for loop
body: <p>I have 2 integers.</p>
  
  <pre><code>$a = 5;
  $b = 3;
  </code></pre>
  
  <p>This is my code as of now, I want to do it vice versa, which is to get the integer that does not exist.
  Instead of getting the existing numbers which are 1,2,3. I would like to execute a command on the numbers  that does not exist (4 &amp; 5).</p>
  
  <pre><code>for ($x = 1; $x &lt;= $a; $x++) {
      for ($y = 1; $y &lt;= $b; $y++) {
          if ($x == $y)
          {
              echo $y." = Exist Do some commands here&lt;br&gt;";
          }
      }
  }
  </code></pre>