parameters: (self, column_name='id', start=0)
return_statement: return new_sf
docstring: Returns a new SFrame with a new column that numbers each row
          sequentially. By default the count starts at 0, but this can be changed
          to a positive or negative number.  The new column will be named with
          the given column name.  An error will be raised if the given column
          name already exists in the SFrame.
  
          Parameters
          ----------
          column_name : str, optional
              The name of the new column that will hold the row numbers.
  
          start : int, optional
              The number used to start the row number count.
  
          Returns
          -------
          out : SFrame
              The new SFrame with a column name
  
          Notes
          -----
          The range of numbers is constrained by a signed 64-bit integer, so
          beware of overflow if you think the results in the row number column
          will be greater than 9 quintillion.
  
          Examples
          --------
          >>> sf = graphlab.SFrame({'a': [1, None, None], 'b': ['a', 'b', None]})
          >>> sf.add_row_number()
          +----+------+------+
          | id |  a   |  b   |
          +----+------+------+
          | 0  |  1   |  a   |
          | 1  | None |  b   |
          | 2  | None | None |
          +----+------+------+
          [3 rows x 3 columns]
docstring_summary: Returns a new SFrame with a new column that numbers each row
          sequentially. By default the count starts at 0, but this can be changed
          to a positive or negative number.  The new column will be named with
          the given column name.  An error will be raised if the given column
          name already exists in the SFrame.
docstring_tokens: Returns a new SFrame with a new column that numbers each row sequentially . By default the count starts at 0 but this can be changed to a positive or negative number . The new column will be named with the given column name . An error will be raised if the given column name already exists in the SFrame .
function: def add_row_number(self, column_name='id', start=0):
          """
          Returns a new SFrame with a new column that numbers each row
          sequentially. By default the count starts at 0, but this can be changed
          to a positive or negative number.  The new column will be named with
          the given column name.  An error will be raised if the given column
          name already exists in the SFrame.
  
          Parameters
          ----------
          column_name : str, optional
              The name of the new column that will hold the row numbers.
  
          start : int, optional
              The number used to start the row number count.
  
          Returns
          -------
          out : SFrame
              The new SFrame with a column name
  
          Notes
          -----
          The range of numbers is constrained by a signed 64-bit integer, so
          beware of overflow if you think the results in the row number column
          will be greater than 9 quintillion.
  
          Examples
          --------
          >>> sf = graphlab.SFrame({'a': [1, None, None], 'b': ['a', 'b', None]})
          >>> sf.add_row_number()
          +----+------+------+
          | id |  a   |  b   |
          +----+------+------+
          | 0  |  1   |  a   |
          | 1  | None |  b   |
          | 2  | None | None |
          +----+------+------+
          [3 rows x 3 columns]
          """
  
          if type(column_name) is not str:
              raise TypeError("Must give column_name as strs")
  
          if type(start) is not int:
              raise TypeError("Must give start as int")
  
          if column_name in self.column_names():
              raise RuntimeError("Column '" + column_name + "' already exists in the current SFrame")
  
          the_col = _create_sequential_sarray(self.num_rows(), start)
  
          # Make sure the row number column is the first column
          new_sf = SFrame()
          new_sf.add_column(the_col, column_name)
          new_sf.add_columns(self)
          return new_sf
function_tokens: def add_row_number ( self , column_name = 'id' , start = 0 ) : if type ( column_name ) is not str : raise TypeError ( "Must give column_name as strs" ) if type ( start ) is not int : raise TypeError ( "Must give start as int" ) if column_name in self . column_names ( ) : raise RuntimeError ( "Column '" + column_name + "' already exists in the current SFrame" ) the_col = _create_sequential_sarray ( self . num_rows ( ) , start ) # Make sure the row number column is the first column new_sf = SFrame ( ) new_sf . add_column ( the_col , column_name ) new_sf . add_columns ( self ) return new_sf