Substring being searched.
    start : int
        Left edge index.
    end : int
        Right edge index.

    Returns
    -------
    Series or Index of int.

    See Also
    --------
    %(also)s

    Examples
    --------
    For Series.str.find:

    >>> ser = pd.Series(["cow_", "duck_", "do_ve"])
    >>> ser.str.find("_")
    0   3
    1   4
    2   2
    dtype: int64

    For Series.str.rfind:

    >>> ser = pd.Series(["_cow_", "duck_", "do_v_e"])
    >>> ser.str.rfind("_")
    0   4
    1   4
    2   4
    dtype: int64
    Ú