121 lines
3.1 KiB
Python
121 lines
3.1 KiB
Python
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# -*- coding: utf-8 -*-
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# This file is part of convertdate.
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# http://github.com/fitnr/convertdate
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# Licensed under the MIT license:
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# http://opensource.org/licenses/MIT
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# Copyright (c) 2016, fitnr <fitnr@fakeisthenewreal>
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import math
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import calendar
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TROPICALYEAR = 365.24219878 # Mean solar tropical year
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def ceil(x):
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return int(math.ceil(x))
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def floor(x):
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return int(math.floor(x))
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def amod(a, b):
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'''Modulus function which returns numerator if modulus is zero'''
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modded = int(a % b)
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return b if modded == 0 else modded
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# Sane people of the world, use calendar.weekday!
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def jwday(j):
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'''Calculate day of week from Julian day'''
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return math.trunc((j + 0.5)) % 7
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def weekday_before(weekday, jd):
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return jd - jwday(jd - weekday)
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# @param weekday Day of week desired, 0 = Monday
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# @param jd Julian date to begin search
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# @param direction 1 = next weekday, -1 = last weekday
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# @param offset Offset from jd to begin search
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def search_weekday(weekday, jd, direction, offset):
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'''Determine the Julian date for the next or previous weekday'''
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return weekday_before(weekday, jd + (direction * offset))
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# Utility weekday functions, just wrappers for search_weekday
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def nearest_weekday(weekday, jd):
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return search_weekday(weekday, jd, 1, 3)
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def next_weekday(weekday, jd):
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return search_weekday(weekday, jd, 1, 7)
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def next_or_current_weekday(weekday, jd):
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return search_weekday(weekday, jd, 1, 6)
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def previous_weekday(weekday, jd):
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return search_weekday(weekday, jd, -1, 1)
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def previous_or_current_weekday(weekday, jd):
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return search_weekday(weekday, jd, 1, 0)
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def n_weeks(weekday, jd, nthweek):
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j = 7 * nthweek
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if nthweek > 0:
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j += previous_weekday(weekday, jd)
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else:
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j += next_weekday(weekday, jd)
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return j
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def monthcalendarhelper(start_weekday, month_length):
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end_weekday = start_weekday + (month_length - 1) % 7
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lpad = (start_weekday + 1) % 7
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rpad = (5 - end_weekday % 7) % 6
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days = [None] * lpad + list(range(1, 1 + month_length)) + rpad * [None]
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return [days[i:i + 7] for i in range(0, len(days), 7)]
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def nth_day_of_month(n, weekday, month, year):
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"""
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Return (year, month, day) tuple that represents nth weekday of month in year.
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If n==0, returns last weekday of month. Weekdays: Monday=0
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"""
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if not 0 <= n <= 5:
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raise IndexError("Nth day of month must be 0-5. Received: {}".format(n))
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if not 0 <= weekday <= 6:
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raise IndexError("Weekday must be 0-6")
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firstday, daysinmonth = calendar.monthrange(year, month)
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# Get first WEEKDAY of month
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first_weekday_of_kind = 1 + (weekday - firstday) % 7
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if n == 0:
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# find last weekday of kind, which is 5 if these conditions are met, else 4
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if first_weekday_of_kind in [1, 2, 3] and first_weekday_of_kind + 28 <= daysinmonth:
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n = 5
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else:
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n = 4
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day = first_weekday_of_kind + ((n - 1) * 7)
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if day > daysinmonth:
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raise IndexError("No {}th day of month {}".format(n, month))
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return (year, month, day)
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