title: What do ellipsis [...] mean in a list?
body: <p>I was playing around in python. I used the following code in IDLE:</p>
  
  <pre><code>p  = [1, 2]
  p[1:1] = [p]
  print p
  </code></pre>
  
  <p>The output was: </p>
  
  <pre><code>[1, [...], 2]
  </code></pre>
  
  <p>What is this <code>[…]</code>? Interestingly I could now use this as a list of list of list up to infinity i.e.</p>
  
  <pre><code>p[1][1][1]....
  </code></pre>
  
  <p>I could write the above as long as I wanted and it would  still work.</p>
  
  <p>EDIT:</p>
  
  <ul>
  <li>How is it represented in memory?</li>
  <li>What's its use? Examples of some cases where it is useful would be helpful.</li>
  <li>Any link to official documentation would be really useful.</li>
  </ul>