title: regexp logic and or
body: <p>I know there are logical operators such as <code>|</code> "the OR operator" which can be used like this:</p>
  
  <pre><code>earth|world
  </code></pre>
  
  <p>I was wondering how I could check if my string contains earth AND world.</p>
  
  <p>regards,
  alexander</p>