title: What is itertools.groupby() used for?
body: <p>While reading the python documentation I came across the <code>itertools.groupby()</code>
  function. It was not very straightforward so I decided to look up some info here on stackoverflow. I found something from <a href="https://stackoverflow.com/questions/773/how-do-i-use-pythons-itertools-groupby">How do I use Python&#39;s itertools.groupby()?</a>.</p>
  
  <p>There seems to be little info about it here and in the documentation so I decided I to post my observations for comments.</p>
  
  <p>Thanks</p>