workalendar.py

When you're dealing with dates, you're often dealing with dates when folks might not be working. This includes holidays and they can be very tricky to get right, especially when you're dealing with multiple countries. In these situations though, you really want to check out workalendar.

from datetime import date
from workalendar.europe import Netherlands

cal = Netherlands(include_carnival=True)
cal.holidays(2021)

This returns a list of tuples.

[(datetime.date(2021, 1, 1), 'New year'),
 (datetime.date(2021, 2, 14), 'Carnival'),
 (datetime.date(2021, 2, 15), 'Carnival'),
 (datetime.date(2021, 2, 16), 'Carnival'),
 (datetime.date(2021, 4, 2), 'Good Friday'),
 (datetime.date(2021, 4, 4), 'Easter Sunday'),
 (datetime.date(2021, 4, 5), 'Easter Monday'),
 (datetime.date(2021, 4, 27), "King's day"),
 (datetime.date(2021, 5, 5), 'Liberation Day'),
 (datetime.date(2021, 5, 13), 'Ascension Thursday'),
 (datetime.date(2021, 5, 23), 'Whit Sunday'),
 (datetime.date(2021, 5, 24), 'Whit Monday'),
 (datetime.date(2021, 12, 25), 'Christmas Day'),
 (datetime.date(2021, 12, 26), 'Boxing Day')]

You can also check if a date is a "working date" directly.

cal.is_working_day(date(2020, 12, 23)) # True
cal.is_working_day(date(2020, 12, 25)) # False

Another useful function is to check the number of working days between two dates.

cal.get_working_days_delta(date(2018, 4, 2), date(2018, 6, 17))

Pandas

A common use-case for this package will be to use it together with pandas, so we've added a demo snippet below that shows you the fast way to check if a date is a holiday.

import pandas as pd

# Make a pandas series with holidays of interest
holidates = cal.holidays(2020) + cal.holidays(2021) + cal.holidays(2022)
pd_holidays = pd.to_datetime([d[0] for d in holidates])

# Use vectorised (fast!) .isin method to compare dates
df = pd.DataFrame({"date": pd.date_range(start='2020-01-01', end='2022-01-01')})
df.assign(holiday=lambda d: d['date'].isin(pd_holidays)).loc[lambda d: d['holiday']]