title: Key-value from long list of similar items
body: <p>I have a list of Python dictionaries which looks like this:</p>
  
  <pre class="lang-py prettyprint-override"><code>[{'actual': 4.99, 'estimate': 4.55, 'period': '2019-12-31', 'symbol': 'AAPL'}, 
   {'actual': 3.03, 'estimate': 2.84, 'period': '2019-09-30', 'symbol': 'AAPL'}, 
   {'actual': 2.18, 'estimate': 2.1,  'period': '2019-06-30', 'symbol': 'AAPL'}]
  </code></pre>
  
  <p>I need to extract the actual and estimate values for each period. Then I need to divide these values by each other.</p>