old_contents: # Title: Collapse multiple columns of an SFrame into a single column of type list/dict
  
  import graphlab as gl
  
  sf = gl.SFrame({'business': [1,2,3,4], 
                  'category.retail': [1, None, 1, None],
                  'category.food': [1, 1, None, 1],
                  'category.service': [None, 1, 1, None],
                  'category.shop': [1, 1, None, 1]})
  
  # Pack the SFrame columns into a list
  # +----------+--------------------+
  # | business |      category      |
  # +----------+--------------------+
  # |    1     |  [1, 1, None, 1]   |
  # |    2     |  [1, None, 1, 1]   |
  # |    3     | [None, 1, 1, None] |
  # |    4     | [1, None, None, 1] |
  # +----------+--------------------+
  sf_packed_list = sf.pack_columns(column_prefix='category', 
                                   new_column_name='category')
  
  # Pack the columns into a dict
  # +----------+--------------------------------+
  # | business |            category            |
  # +----------+--------------------------------+
  # |    1     | {'food': 1, 'shop': 1, 're ... |
  # |    2     | {'food': 1, 'shop': 1, 'se ... |
  # |    3     |  {'retail': 1, 'service': 1}   |
  # |    4     |     {'food': 1, 'shop': 1}     |
  # +----------+--------------------------------+
  sf_packed_dict  = sf.pack_columns(column_prefix='category', dtype=dict, 
                                    new_column_name='category')
  
  
new_contents: import graphlab as gl
  
  sf = gl.SFrame({'business': [1,2,3,4], 
                  'category.retail': [1, None, 1, None],
                  'category.food': [1, 1, None, 1],
                  'category.service': [None, 1, 1, None],
                  'category.shop': [1, 1, None, 1]})
  
  # Pack the SFrame columns into a list
  # +----------+--------------------+
  # | business |      category      |
  # +----------+--------------------+
  # |    1     |  [1, 1, None, 1]   |
  # |    2     |  [1, None, 1, 1]   |
  # |    3     | [None, 1, 1, None] |
  # |    4     | [1, None, None, 1] |
  # +----------+--------------------+
  sf_packed_list = sf.pack_columns(column_prefix='category', 
                                   new_column_name='category')
  
  # Pack the columns into a dict
  # +----------+--------------------------------+
  # | business |            category            |
  # +----------+--------------------------------+
  # |    1     | {'food': 1, 'shop': 1, 're ... |
  # |    2     | {'food': 1, 'shop': 1, 'se ... |
  # |    3     |  {'retail': 1, 'service': 1}   |
  # |    4     |     {'food': 1, 'shop': 1}     |
  # +----------+--------------------------------+
  sf_packed_dict  = sf.pack_columns(column_prefix='category', dtype=dict, 
                                    new_column_name='category')
  
  
subject: Update sframe_pack.py