title: Pandas: Convert the dateformat of an entire column
body: <p>I have a pandas column df["date"] that provides output like 43374.11, meaning it starts counting from 1900-01-01.</p>
  
  <p>I would like to convert that column to YYYY-MM-DD format.</p>
  
  <p>I tried the following code:</p>
  
  <pre><code>date_conv= datetime.date(1900, 1, 1) +
  datetime.timedelta(int(df["date"]))
  df["date"] =   date_conv.strftime('%Y-%m-%d')
  </code></pre>
  
  <p>However, I get the following error:</p>
  
  <blockquote>
    <p>TypeError: cannot convert the series to class 'int'></p>
  </blockquote>