title: Find if a string DOES NOT contain another string
body: <p>I'm trying to figure out a way to detect if a string DOES NOT contain another string.</p>
  
  <p>Right now I can use strpos like so:</p>
  
  <pre><code>&lt;?php
  
          $ch = curl_init();
          curl_setopt($ch, CURLOPT_URL, "http://www.wra.net/calendar/calendar_4.ics");
          curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
          curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
          curl_setopt($ch, CURLOPT_TIMEOUT, 5);
          $page = curl_exec($ch);
          $page = explode("BEGIN:VEVENT", $page);
          echo "&lt;pre&gt;";
          for ($i=1; $page[$i] != ""; $i++) { 
              $res = explode("SUMMARY:", $page[$i]);
              $res = explode("DESCRIPTION:", $res[1]);
              if (strpos($res[0], "Gallery") !== false) {
                  //do nothing
              } else {
                  //echo "BEGIN:VEVENT".$page[$i];
                  echo $res[0].PHP_EOL;
              }
          }
          echo "&lt;/pre&gt;";
      ?&gt;
  </code></pre>
  
  <p>but obviously that's not a preferred way to do it.</p>
  
  <p>Anyone know of a function or workaround that is cleaner?</p>