Question

如何使用Python生成重复日期？例如，我想为“每个第二个月的第三个星期五”生成重复日期。我想生成每日，每周，每月，每年的重复日期（即与Outlook Express中的重复功能相同）。

Answer 1

import dateutil.rrule as dr
import dateutil.parser as dp
import dateutil.relativedelta as drel

start=dp.parse("19/02/2010")   # Third Friday in Feb 2010

这会产生每个月的第三个星期五

rr = dr.rrule(dr.MONTHLY,byweekday=drel.FR(3),dtstart=start, count=10)

每隔三个星期五打印一次：

print map(str,rr)
# ['2010-02-19 00:00:00', '2010-03-19 00:00:00', '2010-04-16 00:00:00', '2010-05-21 00:00:00', '2010-06-18 00:00:00', '2010-07-16 00:00:00', '2010-08-20 00:00:00', '2010-09-17 00:00:00', '2010-10-15 00:00:00', '2010-11-19 00:00:00']

rr是可迭代的，因此您可以使用切片表示法来挑选其他所有项目。这将打印每隔一个月的第三个星期五：

print map(str,rr[::2])
# ['2010-02-19 00:00:00', '2010-04-16 00:00:00', '2010-06-18 00:00:00', '2010-08-20 00:00:00', '2010-10-15 00:00:00']

上面，我使用str来稍微美化输出。要获得更灵活的日期字符串格式，请使用strftime：有关所有选项，请参阅http://au2.php.net/strftime或strftime的手册页。

print [d.strftime('%d/%m/%Y') for d in rr[::2]]
# ['19/02/2010', '16/04/2010', '18/06/2010', '20/08/2010', '15/10/2010']

Answer 2

你可以试试dateutil - 特别是它的相对分数和套餐。

Answer 3

您可以尝试自己写一下。您将首先需要一个迭代器，它生成以给定间隔分隔的日期：

import datetime

def dateiter(start, resolution):
    date = start
    while True:
            yield date
            date += resolution

现在，您可以生成日期并过滤它们：

# generate a list of every tuesday of february
# this iterates over every day from now, and filtered according to the rules
# warning: infinite generator below, there is nothing to end the iteration
tuesdays_of_february = (date for date in dateiter(datetime.datetime.now(), datetime.timedelta(days=1)) if date.weekday() == 4 and date.month == 2)

你可以自己调用迭代器，直到你有足够的日期：

>>> next(tuesdays_of_february)
datetime.datetime(2010, 2, 19, 14, 25, 46, 171000)

现在，您需要限制结果：

>>> from itertools import *
>>> 
>>> # get the five next valid dates:
>>> list(islice(tuesdays_of_february),5)
[datetime.datetime(2010, 2,26, 14, 25, 46, 171000), datetime.datetime(2011, 2, 4
, 14, 25, 46, 171000), datetime.datetime(2011, 2, 11, 14, 25, 46, 171000), datet
ime.datetime(2011, 2, 18, 1    4, 25, 46, 171000), datetime.datetime(2011, 2, 25
, 14, 25, 46, 171000)]
>>> 
>>> # or until a condition is met:
>>> list(takewhile( lambda date: date.year < 2014, tuesdays_of_february ))
[datetime.datetime(2012, 2, 3, 14, 25, 46, 171000), datetime.datetime(2012, 2, 1
0, 14, 25, 46, 171000), datetime.datetime(2012, 2, 17, 14, 25, 46, 171000), date
time.datetime(2012, 2, 24, 14, 25, 46, 171000), datetime.datetime(2013, 2, 1, 14
, 25, 46, 171000), datetime.datetime(2013, 2, 8, 14, 25, 46, 171000), datetime.d
atetime(2013, 2, 15, 14, 25, 46, 171000), datetime.datetime(2013, 2, 22, 14, 25,
 46, 171000)]

不要忘记查看datetime模块的文档。

使用python生成重复日期？

3 个答案: