title: PO Box regex help to match trailing digits
body: <p>I have the following regex from regex lib that does a fine job to catch some PO Box variations. The only thing it does not do is to match trailing digits:</p>
  
  <p><strong>PO Box 123</strong></p>
  
  <p>Can anyone please help modifying this regex to also match trailing digits?</p>
  
  <pre><code>\b[P|p]?(OST|ost)?\.?\s*[O|o|0]?(ffice|FFICE)?\.?\s*[B|b][O|o|0]?[X|x]?\.?\s+[#]?(\d+)\b
  </code></pre>
  
  <p>Thanks.</p>