code: def get_row_list(self, row_idx):
          
  
          try:
              row = self._rows[row_idx]
          except TypeError:
              row = self._rows[self._row_name_idx[row_idx]]
  
          if isinstance(row, list):
              extra = [ self._default_value ] * (len(self._column_name_list) - len(row))
              return row + extra
  
          else:
              if row_idx not in self._row_memo:
                  self._row_memo[row_idx] = [ row[k] if k in row else self._default_value for k in self._column_name_list ]
  
              return self._row_memo[row_idx]
docs: get a feature vector for the nth row
  
          :param row_idx: which row
          :return: a list of feature values, ordered by column_names