Closes bpo-28292: Implemented Calendar.itermonthdays3() and itermonthdays4(). (#4079)

Calendar.itermonthdates() will now consistently raise an exception when a date falls outside of the 0001-01-01 through 9999-12-31 range. To support applications that cannot tolerate such exceptions, the new methods itermonthdays3() and itermonthdays4() are added. The new methods return tuples and are not restricted by the range supported by datetime.date.

Thanks @serhiy-storchaka for suggesting the itermonthdays4() method and for the review.
This commit is contained in:
Alexander Belopolsky 2017-10-24 13:17:10 -04:00 committed by GitHub
parent eab3ff72eb
commit fdd9b217c6
4 changed files with 101 additions and 35 deletions

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@ -53,17 +53,40 @@ it's the base calendar for all computations.
month that are required to get a complete week.
.. method:: itermonthdays2(year, month)
Return an iterator for the month *month* in the year *year* similar to
:meth:`itermonthdates`. Days returned will be tuples consisting of a day
number and a week day number.
.. method:: itermonthdays(year, month)
Return an iterator for the month *month* in the year *year* similar to
:meth:`itermonthdates`. Days returned will simply be day numbers.
:meth:`itermonthdates`, but not restricted by the :class:`datetime.date`
range. Days returned will simply be day of the month numbers. For the
days outside of the specified month, the day number is ``0``.
.. method:: itermonthdays2(year, month)
Return an iterator for the month *month* in the year *year* similar to
:meth:`itermonthdates`, but not restricted by the :class:`datetime.date`
range. Days returned will be tuples consisting of a day of the month
number and a week day number.
.. method:: itermonthdays3(year, month)
Return an iterator for the month *month* in the year *year* similar to
:meth:`itermonthdates`, but not restricted by the :class:`datetime.date`
range. Days returned will be tuples consisting of a year, a month and a day
of the month numbers.
.. versionadded:: 3.7
.. method:: itermonthdays4(year, month)
Return an iterator for the month *month* in the year *year* similar to
:meth:`itermonthdates`, but not restricted by the :class:`datetime.date`
range. Days returned will be tuples consisting of a year, a month, a day
of the month, and a day of the week numbers.
.. versionadded:: 3.7
.. method:: monthdatescalendar(year, month)

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@ -126,6 +126,24 @@ def monthrange(year, month):
return day1, ndays
def monthlen(year, month):
return mdays[month] + (month == February and isleap(year))
def prevmonth(year, month):
if month == 1:
return year-1, 12
else:
return year, month-1
def nextmonth(year, month):
if month == 12:
return year+1, 1
else:
return year, month+1
class Calendar(object):
"""
Base calendar class. This class doesn't do any formatting. It simply
@ -157,28 +175,8 @@ class Calendar(object):
values and will always iterate through complete weeks, so it will yield
dates outside the specified month.
"""
date = datetime.date(year, month, 1)
# Go back to the beginning of the week
days = (date.weekday() - self.firstweekday) % 7
date -= datetime.timedelta(days=days)
oneday = datetime.timedelta(days=1)
while True:
yield date
try:
date += oneday
except OverflowError:
# Adding one day could fail after datetime.MAXYEAR
break
if date.month != month and date.weekday() == self.firstweekday:
break
def itermonthdays2(self, year, month):
"""
Like itermonthdates(), but will yield (day number, weekday number)
tuples. For days outside the specified month the day number is 0.
"""
for i, d in enumerate(self.itermonthdays(year, month), self.firstweekday):
yield d, i % 7
for y, m, d in self.itermonthdays3(year, month):
yield datetime.date(y, m, d)
def itermonthdays(self, year, month):
"""
@ -192,6 +190,40 @@ class Calendar(object):
days_after = (self.firstweekday - day1 - ndays) % 7
yield from repeat(0, days_after)
def itermonthdays2(self, year, month):
"""
Like itermonthdates(), but will yield (day number, weekday number)
tuples. For days outside the specified month the day number is 0.
"""
for i, d in enumerate(self.itermonthdays(year, month), self.firstweekday):
yield d, i % 7
def itermonthdays3(self, year, month):
"""
Like itermonthdates(), but will yield (year, month, day) tuples. Can be
used for dates outside of datetime.date range.
"""
day1, ndays = monthrange(year, month)
days_before = (day1 - self.firstweekday) % 7
days_after = (self.firstweekday - day1 - ndays) % 7
y, m = prevmonth(year, month)
end = monthlen(y, m) + 1
for d in range(end-days_before, end):
yield y, m, d
for d in range(1, ndays + 1):
yield year, month, d
y, m = nextmonth(year, month)
for d in range(1, days_after + 1):
yield y, m, d
def itermonthdays4(self, year, month):
"""
Like itermonthdates(), but will yield (year, month, day, day_of_week) tuples.
Can be used for dates outside of datetime.date range.
"""
for i, (y, m, d) in enumerate(self.itermonthdays3(year, month)):
yield y, m, d, (self.firstweekday + i) % 7
def monthdatescalendar(self, year, month):
"""
Return a matrix (list of lists) representing a month's calendar.

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@ -502,10 +502,15 @@ class CalendarTestCase(unittest.TestCase):
new_october = calendar.TextCalendar().formatmonthname(2010, 10, 10)
self.assertEqual(old_october, new_october)
def test_itermonthdates(self):
# ensure itermonthdates doesn't overflow after datetime.MAXYEAR
# see #15421
list(calendar.Calendar().itermonthdates(datetime.MAXYEAR, 12))
def test_itermonthdays3(self):
# ensure itermonthdays3 doesn't overflow after datetime.MAXYEAR
list(calendar.Calendar().itermonthdays3(datetime.MAXYEAR, 12))
def test_itermonthdays4(self):
cal = calendar.Calendar(firstweekday=3)
days = list(cal.itermonthdays4(2001, 2))
self.assertEqual(days[0], (2001, 2, 1, 3))
self.assertEqual(days[-1], (2001, 2, 28, 2))
def test_itermonthdays(self):
for firstweekday in range(7):
@ -846,7 +851,8 @@ class MiscTestCase(unittest.TestCase):
blacklist = {'mdays', 'January', 'February', 'EPOCH',
'MONDAY', 'TUESDAY', 'WEDNESDAY', 'THURSDAY', 'FRIDAY',
'SATURDAY', 'SUNDAY', 'different_locale', 'c',
'prweek', 'week', 'format', 'formatstring', 'main'}
'prweek', 'week', 'format', 'formatstring', 'main',
'monthlen', 'prevmonth', 'nextmonth'}
support.check__all__(self, calendar, blacklist=blacklist)

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@ -0,0 +1,5 @@
Calendar.itermonthdates() will now consistently raise an exception when a
date falls outside of the 0001-01-01 through 9999-12-31 range. To support
applications that cannot tolerate such exceptions, the new methods
itermonthdays3() and itermonthdays4() are added. The new methods return
tuples and are not restricted by the range supported by datetime.date.