Using pandas AbstractHolidayCalendar to calculate work days

japanese_business_calendar.py

import datetime
from pandas.tseries.holiday import AbstractHolidayCalendar, Holiday, sunday_to_monday, MO
from pandas.tseries.offsets import Day, CustomBusinessDay, DateOffset


class JapanBusinessCalendar(AbstractHolidayCalendar):
    rules = [
        Holiday('New Years Day', month=1, day=1),
        Holiday('Coming of Age Day', month=1, day=8),  # second monday of Jan
        Holiday('National Foundation Day', month=2, day=11, observance=sunday_to_monday),  # observed monday if falls on Sunday
        Holiday('Vernal Equinox Day', month=3, day=21),  # date of the holiday is not officially declared until February of the previous year, due to the need for recent astronomical measurements.
        
        # golden week
        # The days which are holidays each year depend on how the holidays fall in combination with the two weekends either side of Golden Week.
        Holiday('Showa Day', month=4, day=29, observance=sunday_to_monday),  # observance (unclear)
        Holiday('Constitution Memorial day', month=5, day=3),  # observance (unclear)
        Holiday('Greenery Day', month=5, day=4), # observance (unclear)
        Holiday('Childrens Day', month=5, day=4), # observance (unclear)
        

        Holiday('Marine Day', month=7, day=16),
        Holiday('Mountain Day', month=8, day=11, observance=sunday_to_monday), # observed monday if falls on Sunday
        Holiday('Respect for the Aged Day', month=9, day=18, offset=DateOffset(weekday=MO(3))),  # 3rd Monday of Sept
        Holiday('Autumnal Equinox Day', month=9, day=23),  # 23/24
        Holiday('Health-Sports Day', month=10, day=9, offset=DateOffset(weekday=MO(2))),  # 2nd Monday of October
        Holiday('Culture Day', month=11, day=3, observance=sunday_to_monday), # observed monday if falls on Sunday
        Holiday('Labour Day', month=11, day=23, observance=sunday_to_monday), # observed monday if falls on Sunday
        Holiday('Emperors Birthday', month=12, day=23, observance=sunday_to_monday), # observed monday if falls on Sunday
    ]


JAPAN_BUSINESS_DAY_OFFSET = CustomBusinessDay(calendar=JapanBusinessCalendar())

# usage example
current = datetime.datetime(2018, 7, 11)
days_to_work = 15
work_dates = []
for i in range(days_to_work):
  current += JAPAN_BUSINESS_DAY_OFFSET  # changes to pandas timestamp object
  work_dates.append(current.to_pydatetime())