title: Calculate Time Difference Between Two Pandas Columns in Hours and Minutes
body: <p>I have two columns, <code>fromdate</code> and <code>todate</code>, in a dataframe.</p>
  <pre class="lang-py prettyprint-override"><code>import pandas as pd
  
  data = {'todate': [pd.Timestamp('2014-01-24 13:03:12.050000'), pd.Timestamp('2014-01-27 11:57:18.240000'), pd.Timestamp('2014-01-23 10:07:47.660000')],
          'fromdate': [pd.Timestamp('2014-01-26 23:41:21.870000'), pd.Timestamp('2014-01-27 15:38:22.540000'), pd.Timestamp('2014-01-23 18:50:41.420000')]}
  
  df = pd.DataFrame(data)
  </code></pre>
  <p>I add a new column, <code>diff</code>, to find the difference between the two dates using</p>
  <pre class="lang-py prettyprint-override"><code>df['diff'] = df['fromdate'] - df['todate']
  </code></pre>
  <p>I get the <code>diff</code> column, but it contains <code>days</code>, when there's more than 24 hours.</p>
  <pre class="lang-py prettyprint-override"><code>                   todate                fromdate                   diff
  0 2014-01-24 13:03:12.050 2014-01-26 23:41:21.870 2 days 10:38:09.820000
  1 2014-01-27 11:57:18.240 2014-01-27 15:38:22.540 0 days 03:41:04.300000
  2 2014-01-23 10:07:47.660 2014-01-23 18:50:41.420 0 days 08:42:53.760000
  </code></pre>
  <p>How do I convert my results to only hours and minutes (i.e. days are converted to hours)?</p>