Pandas BDay Not Recognizing Juneteenth-CodePudding

How can I override BDay function so recognizes Juneteenth? Using pandas-1.4.2

from datetime import date
from pandas.tseries.offsets import BDay

date(2022,6,17)   BDay(1)

CodePudding user response：

We need to tell pandas about holidays. BusinessDay cannot handle holidays, so we need to replace it with CustomBusinessDay, and tell it which holidays we have.

There are some included in pandas. I'm going to assume US based on your question:

from datetime import date
import pandas.tseries.holiday

holiday_dates = (pandas.tseries.holiday.USFederalHolidayCalendar()
 .holidays(start="2022-01-01", end="2023-01-01"))

# holiday_dates output:
# DatetimeIndex(['2022-01-17', '2022-02-21', '2022-05-30', '2022-06-20',
#                '2022-07-04', '2022-09-05', '2022-10-10', '2022-11-11',
#                '2022-11-24', '2022-12-26'],
#               dtype='datetime64[ns]', freq=None)

So Pandas knows some holidays.

If you use Pandas 1.4 or later, Juneteenth is included in USFederalHolidayCalendar and you should use it directly like this:

from pandas.tseries.offsets import CustomBusinessDay

date(2022,6,17)   CustomBusinessDay(1, holidays=holiday_dates)
# Timestamp('2022-06-21 00:00:00')

With older Pandas, we can let it know about the holiday like the following.

Juneteenth corresponds to June 19th, but seems to fall as a holiday on June 20th in 2022 in particular. Pandas has a rule for this - next workday (if you know the rule more exactly, please update this answer).

This is the long but proper way around to add this as a holiday:

import pandas.tseries.holiday
from pandas.tseries.holiday import next_workday

juneteenth = (pandas.tseries.holiday.Holiday("Juneteenth",
              month=6, day=19, observance=next_workday))
# Holiday: Juneteenth (month=6, day=19, observance=<function next_workday at 0x7f25db280dc0>)

# Now compute the actual dates the holiday will fall on in 2022
# (can be any date or year range)
juneteenth_dates = juneteenth.dates(date(2022,1,1), date(2023,1,1))


from pandas.tseries.offsets import CustomBusinessDay

# Now compute the offset we wanted
date(2022,6,17)   CustomBusinessDay(1, holidays=juneteenth_dates)
# Timestamp('2022-06-21 00:00:00')