split_years_to_months.py

split_years_to_months.py

import datetime
import calendar
import re

def last_day_of_month(date):
    return date.replace(day=31) if date.month == 12 else date.replace(month=date.month+1, day=1) - datetime.timedelta(days=1)

def format_date(date):
    return date.strftime("%Y-%m-%dT%H:%M:%S.%fZ")

def get_interval(start, end):
    return dict(start=format_date(start), end=format_date(end))

def split_years_to_months(start, end, number_of_years):
    days =  0
    number_of_months = 12 * number_of_years
    intervals = []
    #intervals.append(get_interval(start, end))
    intervals.append(get_interval(start,last_day_of_month(start)))

    for i in range(number_of_months-1):

        factored_months = (start.month+i) %12
        factored_months = 12 if factored_months == 0 else factored_months
        factored_year = start.year + (start.month+i // 12)
        days += calendar.monthrange(factored_year, factored_months)[1]
        next_start = start + datetime.timedelta(days=days)
        next_end = last_day_of_month(next_start)
        intervals.append(get_interval(next_start, next_end))

    return intervals

def parse_amount_from_period(period_string):
    """
    Gets the amount from the period string.

        >>> parse_amount_from_period('P10M')
        10
    """
    return int(re.findall(r'\d+', period_string)[0])

if __name__ == '__main__':
    start = datetime.datetime(2019,1,1)
    end = datetime.datetime(2020,12,31)
    number_of_years = parse_amount_from_period("P2Y")
    intervals = split_years_to_months(start, end, number_of_years)
    print(intervals)