pandas.DatetimeIndex.is_month_start — pandas 2.2.3 documentation (original) (raw)

property DatetimeIndex.is_month_start[source]#

Indicates whether the date is the first day of the month.

Returns:

Series or array

For Series, returns a Series with boolean values. For DatetimeIndex, returns a boolean array.

See also

is_month_start

Return a boolean indicating whether the date is the first day of the month.

is_month_end

Return a boolean indicating whether the date is the last day of the month.

Examples

This method is available on Series with datetime values under the .dt accessor, and directly on DatetimeIndex.

s = pd.Series(pd.date_range("2018-02-27", periods=3)) s 0 2018-02-27 1 2018-02-28 2 2018-03-01 dtype: datetime64[ns] s.dt.is_month_start 0 False 1 False 2 True dtype: bool s.dt.is_month_end 0 False 1 True 2 False dtype: bool

idx = pd.date_range("2018-02-27", periods=3) idx.is_month_start array([False, False, True]) idx.is_month_end array([False, True, False])