set

    The values are physically stored as a 1-D ndarray of integers. These are
    called "ordinals" and represent some kind of offset from a base.

    The `freq` indicates the span covered by each element of the array.
    All elements in the PeriodArray have the same `freq`.

    Examples
    --------
    >>> pd.arrays.PeriodArray(pd.PeriodIndex(['2023-01-01',
    ...                                       '2023-01-02'], freq='D'))
    <PeriodArray>
    ['2023-01-01', '2023-01-02']
    Length: 2, dtype: period[D]
    ič