title: DeprecationWarning: The default dtype for empty Series will be 'object' instead of 'float64' in a future version warning
body: <p>I appending a new row to an existing pandas dataframe as follows:</p>
  
  <pre><code>df= df.append(pd.Series(), ignore_index=True)
  </code></pre>
  
  <p>This is resulting in the subject DeprecationWarning.</p>
  
  <p>The existing df has a mix of string, float and dateime.date datatypes (8 columns totals).</p>
  
  <p>Is there a way to explicitly specify the columns types in the df.append?  </p>
  
  <p>I have looked <a href="https://pandas.pydata.org/docs/whatsnew/v1.0.0.html" rel="noreferrer">here</a>  and <a href="https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.DataFrame.append.html" rel="noreferrer">here</a> but I still have no solution.   Please advise if there is a better way to append a row to the end of an existing dataframe without triggering this warning.</p>