title: Cannot astype timedelta using pandas?
body: <p>I got the following error running my code :</p>
  
  <pre><code>    import pandas as pd
      data = pd.read_csv('file.csv')
      data['time'] = pd.to_datetime(data['UNIX time'],unit='s')
      data['time_min'] = (data['time'] - data['time'].min()).astype(int)
  </code></pre>
  
  <p>"cannot astype a timedelta from [timedelta64[ns]] to [int32]"</p>