title: Replace duplicated values with blank in pandas
body: <p>I am working on Pandas data frame.
  The example code will be as follow:
  `
  import pandas as pd</p>
  
  <pre><code>df = pd.DataFrame(
                    {'name1': ['A', 'C', 'A', 'B','C', 'D','D', 'C', 'A', 'B','C', 'A'], 
                     'name2': ['B', 'D', 'C', 'D','B','A','A', 'D', 'C', 'D','D','B'], 
                     'id': [1, 1, 1, 1, 1, 1,2, 2, 2, 2, 2, 2], 
                     'Value1': [1, 2, 3, 4, 5, 6, 0, 2, 4, 6, 3, 5], 
                     'Value2': [0, 2, 4, 6, 3, 5, 1, 2, 3, 4, 5, 6]
                    },
                    columns=['name1','name2','id','Value1','Value2'])`
  </code></pre>
  
  <p>I can do the agg using the following groupby:</p>
  
  <pre><code>m = df.groupby(['id','name1',])['Value1'].sum()
  </code></pre>
  
  <p>When I printed <strong>m</strong>, it will show as follow:</p>
  
  <pre><code>   id  name1
      1   A        4
          B        4
          C        7
          D        6
      2   A        9
          B        6
          C        5
          D        0
      Name: Value1, dtype: int64
  </code></pre>
  
  <p>When I wrote <strong>m</strong> it to csv file, it will only contain the value1 as it is a pandas series.
  Using this series, I want to create a dataframe that is exactly the same as the <strong>table below</strong></p>
  
  <pre><code>  id name1  Value1
    1     A      4
    1     B      4
    1     C      7
    1     D      6
    2     A      9
    2     B      6
    2     C      5
    2     D      0
  </code></pre>
  
  <p>Anyone advise me how to do that?
  Thanks a lot
  Zep</p>