on : Standard library version.

    Examples
    --------

    >>> s = pd.Series(['Linda van der Berg', 'George Pitt-Rivers'])
    >>> s
    0    Linda van der Berg
    1    George Pitt-Rivers
    dtype: object

    >>> s.str.partition()
            0  1             2
    0   Linda     van der Berg
    1  George      Pitt-Rivers

    To partition by the last space instead of the first one:

    >>> s.str.rpartition()
                   0  1            2
    0  Linda van der            Berg
    1         George     Pitt-Rivers

    To partition by something different than a space:

    >>> s.str.partition('-')
                        0  1       2
    0  Linda van der Berg
    1         George Pitt  -  Rivers

    To return a Series containing tuples instead of a DataFrame:

    >>> s.str.partition('-', expand=False)
    0    (Linda van der Berg, , )
    1    (George Pitt, -, Rivers)
    dtype: object

    Also available on indices:

    >>> idx = pd.Index(['X 123', 'Y 999'])
    >>> idx
    Index(['X 123', 'Y 999'], dtype='object')

    Which will create a MultiIndex:

    >>> idx.str.partition()
    MultiIndex([('X', ' ', '123'),
                ('Y', ' ', '999')],
               )

    Or an index with tuples with ``expand=False``:

    >>> idx.str.partition(expand=False)
    Index([('X', ' ', '123'), ('Y', ' ', '999')], dtype='object')
    Z
str_partitionÚ