title: convert days difference to numeric values in python pandas
body: <p>I have a column 'datedif' in my dataframe as :</p>
  
  <pre><code>  exposuredate min_exposure_date    datedif
    2014-10-08   2014-09-27           11 days
    2014-10-09   2014-09-27           12 days
    2014-09-27   2014-09-27           0 days
    2014-09-27   2014-09-27           0 days
    2014-10-22   2014-09-27           25 days
  
    data.exposuredate = pd.to_datetime(data.exposuredate)
    data.min_exposure_date = pd.to_datetime(data.min_exposure_date)
  
    data['datedif'] = ((data.exposuredate)-(data.min_exposure_date))
  </code></pre>
  
  <p>The format for the columns are datetime64[ns]. I want to extract the number of days in the field 'datedif'. I am not able to find anything which could help me to extract the difference in terms of number of days.</p>
  
  <p>I tried:</p>
  
  <pre><code>data['datedif_day'] = data['datedif'].dt.days
  </code></pre>
  
  <p><strong>Error:</strong> </p>
  
  <blockquote>
    <p>AttributeError: 'Series' object has no attribute 'dt'</p>
  </blockquote>