title: Calculate difference of 2 dates in minutes in pandas
body: <p>I have 2 columns  in a dataframe. I want to calculate the difference of  2 columns in minutes and write the result into a new column</p>
  
  <pre><code>Input
  
  Planned Pickup date/time    Actual Pickup date/time      
  07/05/2018 09:28:00         07/05/2018 09:33:15               
  14/05/2018 17:00:00         15/05/2018 08:44:08               
  15/05/2018 17:00:00         15/05/2018 10:52:50              
  15/05/2018 17:00:00         15/05/2018 15:03:34             
  15/05/2018 17:00:00         15/05/2018 15:03:34              
  16/05/2018 17:00:00         16/05/2018 16:00:38   
  </code></pre>
  
  <p>I want to calculate the difference the actual and  planned pickup  in minutes and write the result into a new column in dataframe called  <code>data['time difference']</code></p>
  
  <p><strong><code>Expected Output</code></strong></p>
  
  <pre><code>Planned Pickup date/time    Actual Pickup date/time      Time Difference
  07/05/2018 09:28:00         07/05/2018 09:33:15               5
  14/05/2018 17:00:00         15/05/2018 08:44:08               944
  15/05/2018 17:00:00         15/05/2018 10:52:50              -368
  15/05/2018 17:00:00         15/05/2018 15:03:34              -117
  15/05/2018 17:00:00         15/05/2018 15:03:34              -117
  16/05/2018 17:00:00         16/05/2018 16:00:38              -60
  </code></pre>
  
  <p>How can this done in pandas</p>