title: How to check if the set of numbers contains a certain number in PHP?
body: <p>I'm creating this school project that has this <code>&lt;select&gt;</code> tag where if the <code>&lt;option&gt;</code> value is equal to a certain number, it will not show, display or print.</p>
  
  <p>Example: if the set of numbers is 1,2,4,5,9 then only the <code>&lt;option&gt;</code> tag that has a value of 3,6,7,8,10,11,12 will show.</p>
  
  <pre><code>&lt;select name=""&gt;
      &lt;?php
          $set_of_numbers = "1,2,4,5,9";
  
          for($i=0; $i&lt;=12; $i++) {
              if($i != $set_of_numbers) {
                 echo '&lt;option value='.$i.'&gt;'.$i.'&lt;/option&gt;';
              }
          }
       ?&gt;
   &lt;/select&gt;
  </code></pre>