title: Pandas - Python - how to subtract two different date columns
body: <p>Trying to have a column be filled with today's date minus the created_date column, but getting the following error : TypeError: unsupported operand type(s) for -: 'str' and 'str'</p>
  
  <pre><code>import datetime
  now = datetime.date.today()
  today = '{0:%m/%d/%Y}'.format(now).format(now)
  today
  data['Aging'] = today
  data['Aging'] = data['Aging'].sub(data['Created_Date'], axis=0)
  </code></pre>
  
  <p>TypeError: unsupported operand type(s) for -: 'str' and 'str'</p>