Find overlapping dates for Ascension Day and Liberation Day

holiday.py

# Import libraries
import operator
from workalendar.europe import Netherlands


# Settings
start_year = 1945
end_year = 2016
date_month = 5
date_day = 5
date_name = 'Liberation Day'
holiday_name = 'Ascension Thursday'
max_print_rows = 10


def get_suffix(year_list):
    if len(year_list) == 0:
        suffix = '.'
    else:
        suffix = ': in {0}'.format(day_dict[date_string][1][0])
        count_year = 1
        while count_year < len(year_list) - 1:
            suffix += ', ' + str(year_list[count_year])
            count_year += 1
        if len(year_list) > 1:
            suffix += ' and ' + str(year_list[-1])
        suffix += '.'

    return suffix

# Make calendar instance
cal = Netherlands()

# Initialise empty date dictionary for the dates of the holiday
day_dict = {}

# Set the range and date string
year_range = 1 + end_year - start_year

if date_month < 10:
    date_string = '0' + str(date_month) + '-'
else:
    date_string = str(date_month) + '-'
if date_day < 10:
    date_string += '0' + str(date_day)
else:
    date_string += str(date_day)

# Check whether the year range is valid
if year_range < 1:
    raise Exception('end_year may not be smaller than start_year')

for year in range(start_year, end_year+1):
    holidays = cal.holidays(year)

    # Get the holiday for this year
    holiday = next((holiday for holiday in holidays
                    if holiday[1].lower().strip()[:len(holiday_name)] ==
                    holiday_name.lower()), None)
    if holiday:
        # Store the day into the date dictionary
        holiday = holiday[0]
        holiday_date = '0' + str(holiday.month)
        if holiday.day > 9:
            holiday_date += '-' + str(holiday.day)
        else:
            holiday_date += '-0' + str(holiday.day)
        if holiday_date in day_dict:
            day_dict[holiday_date][0] += 1
            day_dict[holiday_date][1].append(year)
        else:
            day_dict[holiday_date] = [1, [year]]
    else:
        raise Exception("No {0} in {1}".format(holiday_name, year))

# Order the date dictionary on descending occurrences
ordered_day_dict = sorted(day_dict.items(), key=operator.itemgetter(1),
                          reverse=True)

# Print statistics
if date_string in day_dict:
    overlap = day_dict[date_string][0]
    suffix_year = get_suffix(day_dict[date_string][1])
else:
    overlap = 0
    suffix_year = '.'

if overlap == 1:
    timing = 'time'
else:
    timing = 'times'

print("Between (and including) {0} and {1}, {2} and {3} occurred {4} {5} on "
      "the same date{6}\n".format(start_year, end_year, date_name,
                                  holiday_name, overlap, timing, suffix_year))

print("Most frequent dates of {0}:".format(holiday_name))
count = 0
for date_value in ordered_day_dict:
    count += 1
    occurrence = date_value[0]
    if occurrence == 1:
        timing = 'time'
    else:
        timing = 'times'

    print("{0}: {1} {2} ({3}%)".format(occurrence, date_value[1][0], timing,
                                       round(100*date_value[1][0]/year_range,
                                             2)))
    if count >= max_print_rows:
        break

requirements.txt

workalendar~=0.4.3