title: Regex Contains No Capture Groups?
body: <p>I've got a series of malformed JSON data that I need to use Regex to get the data I need out of it, then I need to use regex again to remove a specific aspect of the data i.e. the main category, in the example below it's 'games'.</p>
  
  <p>Part 1 works, the second part does not.</p>
  
  <p>I've limited experience with Python, and next to no experience with Regex.</p>
  
  <p><strong>Final Output</strong>: games</p>
  
  <p>I'm getting the error:</p>
  
  <blockquote>
    <p>ValueError: pattern contains no capture groups</p>
  </blockquote>
  
  <p>The series of data contains information formated like this:</p>
  
  <pre><code> {"urls":{"web":{"discover":"http://www.kickstarter.com/discover/categories/games/playing%20cards"}},"color":51627,"parent_id":12,"name":"Playing Cards","id":273,"position":4,"slug":"games/playing cards"}
  </code></pre>
  
  <p>The Python call I'm using is this:</p>
  
  <p>First I remove the slug from the JSON.</p>
  
  <pre><code>ksdata.cat_slug_raw = ksdata.category.str.extract('\"slug\"\:\"(.+?)\"', expand=False)
  </code></pre>
  
  <p>Then I remove everything before the /</p>
  
  <pre><code>ksdata.cat_slug = ksdata.cat_slug_raw.str.extract('^[^/]+(?=/)', expand=False)
  </code></pre>
  
  <p>I'd really appreciate some help with where I'm going wrong...and if you think my solution as a whole sux please tell me :)</p>