title: Django url pattern - string parameter
body: <p>Django url pattern that have a number parameter is:</p>
  
  <pre><code>url(r'^polls/(?P&lt;poll_id&gt;\d+)/$', 'polls.views.detail')
  </code></pre>
  
  <p>What will be the correct syntax if my poll_id is not a number but a string of character?</p>