title: Python Pandas Sum on Date and Description
body: <p>I am using Python 2.7. I have a Pandas data frame that looks like</p>
  
  <pre><code>raw_data = {'Date': ['12/1/2016', '12/4/2016','12/23/2016', '1/18/2017','1/18/2017','1/19/2017'], 
      'Account': ['aa1', 'aa2','aa1', 'aa1', 'aa1', 'aa2'], 
      'Description': ['store1', 'store2','store1', 'store2','store1','store2' ], 
      'Amount': [26.43, 24.99, 31.54,45.32, 2.00, 15.41],
      'Category': ['G','G','G','G','G','G'],
      'Initials': ['FR','DB','FR','DB','FR','FR']}
  df = pd.DataFrame(raw_data, columns = ['Date','Account','Description','Amount','Category','Initials'])
  </code></pre>
  
  <p>I would like to sum by each Description and month so that my data looks like:<br>
  Date Description Amount <br/>
  Dec 2016 store1 57.97 <br/>
  Dec 2016 store2 24.99 <br/>
  Jan 2017 store1 2.00 <br/>
  Jan 2017 store2 60.73<br/></p>
  
  <p>I have written the below code that sums by month but i am stuck on how to incorporate the Description column.</p>
  
  <pre><code>#convert Date to datetimeindex
  df['Date'] = pd.to_datetime(df['Date'])
  df = df.set_index('Date')
  
  #sum by month
  df = df.groupby(pd.TimeGrouper("M")).sum()
  df
  </code></pre>
  
  <p>Any guidance would be much appreciated. Thanks.</p>