pandas.Series.to_period

Series.to_period(freq=None, copy=<no_default>)

Convert Series from DatetimeIndex to PeriodIndex.

Parameters:

freqstr, default None

Frequency associated with the PeriodIndex.

copybool, default False

This keyword is now ignored; changing its value will have no impact on the method.

Deprecated since version 3.0.0: This keyword is ignored and will be removed in pandas 4.0. Since pandas 3.0, this method always returns a new object using a lazy copy mechanism that defers copies until necessary (Copy-on-Write). See the user guide on Copy-on-Write for more details.

Returns:

Series

Series with index converted to PeriodIndex.

See also

DataFrame.to_period

Equivalent method for DataFrame.

Series.dt.to_period

Convert DateTime column values.

Examples

>>> idx = pd.DatetimeIndex(["2023", "2024", "2025"])
>>> s = pd.Series([1, 2, 3], index=idx)
>>> s = s.to_period()
>>> s
2023    1
2024    2
2025    3
Freq: Y-DEC, dtype: int64

Viewing the index

>>> s.index
PeriodIndex(['2023', '2024', '2025'], dtype='period[Y-DEC]')