def __init__(self, df, by):
        """Create a groupby object.

        Parameters
        ----------
        df : DataFrame
            Which will be grouped by.
        by : list of str
            Which columns to group by.

        """
        self._index_df = df[by]
        self._columns_df = df.drop(by)
        self._data_for_weld = df._gather_data_for_weld()
        self._weld_types = df._gather_weld_types()
        self._by = by
        self._by_indices = _compute_by_indices(self._by, df)
def __init__ ( self , df , by ) : self . _index_df = df [ by ] self . _columns_df = df . drop ( by ) self . _data_for_weld = df . _gather_data_for_weld ( ) self . _weld_types = df . _gather_weld_types ( ) self . _by = by self . _by_indices = _compute_by_indices ( self . _by , df )
Create a groupby object.

        Parameters
        ----------
        df : DataFrame
            Which will be grouped by.
        by : list of str
            Which columns to group by.