我在夏令时方面遇到了麻烦。
让我解释一下背景。
我在我的数据库中以UTC格式存储日期。每个用户都有一个时区,我也将这些信息存储在数据库中。
我根据每个用户的时区计算“1个月”的时段。
例如,用户应该看到:
2014-01-06 -> 2014-02-05
2014-02-06 -> 2014-03-05
2014-03-06 -> 2014-04-05
2014-04-06 -> 2014-05-05
2014-05-06 -> 2014-06-05
etc.
夏令时开启或关闭时(3月和11月),我遇到了问题
而不是:
2014-03-06 -> 2014-04-05
,我得到2014-03-06 -> 2014-04-06
2014-11-06 -> 2014-12-05
,我得到2014-11-05 -> 2014-12-04
然后它是所有下一个的偏移量。
我尝试使用UTC日期而不是将它们转换为用户时区,在get_end_date中添加1个月,但我仍有问题。
知道怎么处理这个吗?
由于
这是我的代码和get_end_date方法。
import pytz
from dateutil.parser import parse as parse_date
from dateutil.relativedelta import relativedelta
def to_tz(dt, tz):
tz = pytz.timezone(tz)
return tz.normalize(dt.astimezone(tz))
def get_end_date(dt, tz):
dt_central = to_tz(dt, tz)
# Add 1 month, set hours, minutes, seconds, microseconds to 0 and remove -1 ms
dt_central = dt_central + relativedelta(months=+1)
dt_central = dt_central.replace(hour=0, minute=0, second=0, microsecond=0)
dt_central = dt_central + relativedelta(microseconds=-1)
return to_tz(dt_central, 'UTC')
def print_periods(start_dt, tz, nb_periods=6):
for i in xrange(nb_periods):
print '\n# Period {}'.format(i+1)
end_dt = get_end_date(start_dt, tz)
start_dt_central, end_dt_central = to_tz(start_dt, tz), to_tz(end_dt, tz)
print '{} -> {}'.format(start_dt_central.date(), end_dt_central.date())
print ' > start_dt_central: ', start_dt_central
print ' > end_dt_central: ', end_dt_central
print ' > start_dt: ', start_dt
print ' > end_dt: ', end_dt
start_dt = end_dt + relativedelta(microseconds=1)
输出:
central_tz = 'US/Central'
start_dt = parse_date('2014-01-06 06:00:00+00:00')
In [7]: print_periods(start_dt, central_tz, nb_periods=12)
# Period 1
2014-01-06 -> 2014-02-05
> start_dt_central: 2014-01-06 00:00:00-06:00
> end_dt_central: 2014-02-05 23:59:59.999999-06:00
# Period 2
2014-02-06 -> 2014-03-05
> start_dt_central: 2014-02-06 00:00:00-06:00
> end_dt_central: 2014-03-05 23:59:59.999999-06:00
# Period 3
2014-03-06 -> 2014-04-06
> start_dt_central: 2014-03-06 00:00:00-06:00
> end_dt_central: 2014-04-06 00:59:59.999999-05:00
# Period 4
2014-04-06 -> 2014-05-05
> start_dt_central: 2014-04-06 01:00:00-05:00
> end_dt_central: 2014-05-05 23:59:59.999999-05:00
# Period 5
2014-05-06 -> 2014-06-05
> start_dt_central: 2014-05-06 00:00:00-05:00
> end_dt_central: 2014-06-05 23:59:59.999999-05:00
# Period 6
2014-06-06 -> 2014-07-05
> start_dt_central: 2014-06-06 00:00:00-05:00
> end_dt_central: 2014-07-05 23:59:59.999999-05:00
# Period 7
2014-07-06 -> 2014-08-05
> start_dt_central: 2014-07-06 00:00:00-05:00
> end_dt_central: 2014-08-05 23:59:59.999999-05:00
# Period 8
2014-08-06 -> 2014-09-05
> start_dt_central: 2014-08-06 00:00:00-05:00
> end_dt_central: 2014-09-05 23:59:59.999999-05:00
# Period 9
2014-09-06 -> 2014-10-05
> start_dt_central: 2014-09-06 00:00:00-05:00
> end_dt_central: 2014-10-05 23:59:59.999999-05:00
# Period 10
2014-10-06 -> 2014-11-05
> start_dt_central: 2014-10-06 00:00:00-05:00
> end_dt_central: 2014-11-05 22:59:59.999999-06:00
# Period 11
2014-11-05 -> 2014-12-04
> start_dt_central: 2014-11-05 23:00:00-06:00
> end_dt_central: 2014-12-04 23:59:59.999999-06:00
# Period 12
2014-12-05 -> 2015-01-04
> start_dt_central: 2014-12-05 00:00:00-06:00
> end_dt_central: 2015-01-04 23:59:59.999999-06:00
来自Christian的解决方案1
def get_end_date(dt, tz):
dt_central = to_tz(dt, tz)
orig_tz = dt_central.tzinfo
dt_central = dt_central.replace(tzinfo=None)
# Calculations
dt_central = orig_tz.localize(dt_central)
dt_utc = to_tz(dt_central, 'UTC')
return dt_utc
我自己的解决方案
def get_end_date(dt, tz):
dt_central = to_tz(dt, tz)
# Calculations
dt_utc = to_tz(dt_central, 'UTC')
# When switch to Daylight Saving Time
if to_tz(dt_utc, tz).hour == 0:
dt_utc = dt_utc.replace(hour=dt_utc.hour-1)
# When leave Daylight Saving Time
elif to_tz(dt_utc, tz).hour == 22:
dt_utc = dt_utc.replace(hour=dt_utc.hour+1)
return dt_utc
答案 0 :(得分:3)
我在使用dateutil rrule
时遇到了类似问题,同时扩展了vevent'重现规则。对我有用的是保存时区信息,然后将每个日期时间对象转换为天真日期时间对象,进行计算,然后使用保存的时区将每个日期时间本地化。
这样的话:
orig_tz = dt.tzinfo
dt = dt.replace(tzinfo=None)
# do calculations here
orig_tz.localize(dt)