title: Is there a way to extract the section before the first `/` from a list?
body: <p>I have a list of URLs:</p>
  
  <blockquote>
    <p>URL = ['ose.co.jp/frame.html', 'tse.or.jp/english/individuals/index.html', 'traderupdates.nyse.com/?sa_campaign=/internal_ads/callouts/traderupdates']</p>
  </blockquote>
  
  <p>I thought of using split('/'), but realized that it doesn't really solve the problem because I would still have to delete the portion of the URL after '/'.</p>
  
  <p>The result that I am looking for is:</p>
  
  <pre><code>URL = ['ose.co.jp', 'tse.or.jp', traderupdates.nyse.com']
  </code></pre>