title: Condition for empty dataframe is not satisfied
body: <p>I make queries that I store in a dataframe and then send them to a dictionary, for this it is obvious that the dataframe only contains one record. When there is no information I do something like:</p>
  
  <pre><code>if not df.empty:
      data_q.update({'revenue_week': '{:,}'.format(df.iloc[0].column-name)})
  else:
      data_q.update({'revenue_week': 0})
  </code></pre>
  
  <p>My purpose is that when there are no values, to replace it with <code>0</code>. But doing so it still indicates the dataframe is empty.</p>