Series.dt.
is_month_start
Indicates whether the date is the first day of the month.
For Series, returns a Series with boolean values. For DatetimeIndex, returns a boolean array.
See also
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.
.dt
>>> 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])