zhanying <pytho...@126.com> added the comment:
i read the source code, in this part def _calc_julian_from_U_or_W(year, week_of_year, day_of_week, week_starts_Mon): """Calculate the Julian day based on the year, week of the year, and day of the week, with week_start_day representing whether the week of the year assumes the week starts on Sunday or Monday (6 or 0).""" first_weekday = datetime_date(year, 1, 1).weekday() # If we are dealing with the %U directive (week starts on Sunday), it's # easier to just shift the view to Sunday being the first day of the # week. if not week_starts_Mon: first_weekday = (first_weekday + 1) % 7 day_of_week = (day_of_week + 1) % 7 # Need to watch out for a week 0 (when the first day of the year is not # the same as that specified by %U or %W). week_0_length = (7 - first_weekday) % 7 if week_of_year == 0: return 1 + day_of_week - first_weekday else: days_to_week = week_0_length + (7 * (week_of_year - 1)) return 1 + days_to_week + day_of_week when first_weekday is 0, that year start with Monday, week_of_year equar 0 or 1, this func return same value At 2020-04-09 20:45:51, "Eric V. Smith" <rep...@bugs.python.org> wrote: > >Eric V. Smith <e...@trueblade.com> added the comment: > >Can you tell us what platform you're on? Also, please include the header >that's printed out when you run python from the command line. For example, >mine shows: > >$ python3 >Python 3.7.6 (default, Jan 30 2020, 10:29:04) >[GCC 9.2.1 20190827 (Red Hat 9.2.1-1)] on linux > >---------- >components: +Library (Lib) >nosy: +eric.smith > >_______________________________________ >Python tracker <rep...@bugs.python.org> ><https://bugs.python.org/issue40236> >_______________________________________ ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue40236> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com