title: summarizing a tab separated file in pandas
body: <p>I have big <code>tab separated</code> file like this:</p>
  
  <p><code>small example</code>:</p>
  
  <pre><code>CHTOP   237 122
  CHTOP   64  53
  CHTOP   64  122
  RPS27   986 66
  RPS27   986 50
  RPS27   986 227
  </code></pre>
  
  <p>I want to group the rows according to the 1st column and sum all numbers in the 2nd column which belong the same group and do the same for the numbers in the 3rd column. for instance for the small example we have 2 groups
  the expected output would be:</p>
  
  <p><code>expected output</code>:</p>
  
  <pre><code>CHTOP   365 297
  RPS27   2958    343
  </code></pre>
  
  <p>I used pandas in python but it does not return 3 columns file. </p>
  
  <pre><code>import pandas as pd
  df = pd.read_csv('myfile.txt',sep=None)
  df = df.groupby(['ID']).cumcount()
  df.to_csv('result.txt', sep='\t', index=None)
  </code></pre>
  
  <p>do you know how to fix it?</p>