Python：在一个月的所有天中进行迭代

Question

Is there a simple way to iterate over all days in a given month?

I would like to have a method where the object I'm iterating over has the days as datetime.date objects. I have already found the calendar module with its Calendar class and respective method itermonthdates(year, month) .

My problem with this is that the resulting iterator contains "filler" days to represent complete weeks. For example July 2019 Ends on a Wednesday (31). so the week is incomplete and itermonthdates() adds the dates 1-4 August.

I DO NOT want this behavior.

My first guess is something like:

from calendar import Calendar, monthrange
c = Calendar()

for date in list(c.itermonthdates(2019, 7))[:monthrange(2019, 7)[1]]:
    print(date)

which behaves as expected, but I'm not sure if there is a nicer, more elegant way of doing this.

Answer 1

只需按月过滤date对象。

for d in [x for x in c.itermonthdates(2019, 7) if x.month == 7]:

Answer 2

The calendar module is designed to display calendars. You are better off using calendar.monthlen in combination with datetime.date itself to get your iterator, if you are looking for something straightforward:

def date_iter(year, month):
    for i in range(1, calendar.monthlen(year, month) + 1):
        yield date(year, month, i)

for d in date_iter(2019, 12):
    print(d)

You can of course write the whole thing as a one-liner:

for d in (date(2019, 12, i) for i in range(1, calendar.monthlen(2019, 12) + 1)):
    print(d)

The monthlen attribute appears to be a public, but undocumented attribute of calendar in Python 3.7. It is analogous to the second element of monthrange , so you can replace it with monthrange(year, month)[0] in the code above.