     [
    ...         "this is a regular sentence",
    ...         "https://docs.python.org/3/tutorial/index.html",
    ...         np.nan
    ...     ]
    ... )
    >>> s
    0                       this is a regular sentence
    1    https://docs.python.org/3/tutorial/index.html
    2                                              NaN
    dtype: object

    In the default setting, the string is split by whitespace.

    >>> s.str.split()
    0                   [this, is, a, regular, sentence]
    1    [https://docs.python.org/3/tutorial/index.html]
    2                                                NaN
    dtype: object

    Without the `n` parameter, the outputs of `rsplit` and `split`
    are identical.

    >>> s.str.rsplit()
    0                   [this, is, a, regular, sentence]
    1    [https://docs.python.org/3/tutorial/index.html]
    2                                                NaN
    dtype: object

    The `n` parameter can be used to limit the number of splits on the
    delimiter. The outputs of `split` and `rsplit` are different.

    >>> s.str.split(n=2)
    0                     [this, is, a regular sentence]
    1    [https://docs.python.org/3/tutorial/index.html]
    2                                                NaN
    dtype: object

    >>> s.str.rsplit(n=2)
    0                     [this is a, regular, sentence]
    1    [https://docs.python.org/3/tutorial/index.html]
    2                                                NaN
    dtype: object

    The `pat` parameter can be used to split by other characters.

    >>> s.str.split(pat="/")
    0                         [this is a regular sentence]
    1    [https:, , docs.python.org, 3, tutorial, index...
    2                                                  NaN
    dtype: object

    When using ``expand=True``, the split elements will expand out into
    separate columns. If NaN is present, it is propagated throughout
    the columns during the split.

    >>> s.str.split(expand=True)
                                                   0     1     2        3         4
    0                                           this    is     a  regular  sentence
    1  https://docs.python.org/3/tutorial/index.html  None  None     None      None
    2                                            NaN   NaN   NaN      NaN       NaN

    For slightly more complex use cases like splitting the html document name
    from a url, a combination of parameter settings can be used.

    >>> s.str.rsplit("/", n=1, expand=True)
                                        0           1
    0          this is a regular sentence        None
    1  https://docs.python.org/3/tutorial  index.html
    2                                 NaN         NaN
    %(regex_examples)sÚ	str_splitÚ	beginningz