Hi Serhiy,
I missed the 31st on days range. Thanks for spotting it. I do verify if the
datetime tuple is correct by passing them to datetime() and raising
exception later on on the code (see
https://github.com/Code-ReaQtor/DocCron/blob/1.0.0/doccron/job.py#L180)
Datetime and timedeltas can solve the problem if there is a "pattern" but
this is not an efficient way.
For example, if there are steps on all the categories or the items have no
pattern:
datetime_odometer = itertools.product(
range(2018, 10_000, 5), # year with steps
range(1, 13, 3), # month with steps
range(1, 32, 4), # days with steps
[0, 5, 6, 10, 13, 24], # hours without steps
range(0, 60, 6), # minutes with steps
range(0, 60, 2) # seconds with steps
)
Datetime and timedelta will create a lot of overhead and is not the best
solution. I still believe itertools.product() is the fastest and best
solution.
Let me read the code for __setstate__ first. Thanks for spotting this!
Best Regards,
Ronie Martinez
On Thu, Oct 25, 2018 at 6:22 PM Serhiy Storchaka <[email protected]>
wrote:
> 25.10.18 09:31, Ronie Martinez пише:
> > Here is an example:
> >
> > import itertools
> > import time
> >
> >
> > def main():
> > datetime_odometer = itertools.product(
> > range(2018,10_000),# year
> > range(1,13),# month
> > range(1,31),# days
> > range(0,24),# hours
> > range(0,60),# minutes
> > range(0,60)# seconds
> > )
> >
> > datetime_of_interest = (2050,6,15,10,5,0)
> >
> > for iin datetime_odometer:
> > if i == datetime_of_interest:# target start time
> > break
> >
> >
> > if __name__ =='__main__':
> > start = time.time()
> > main()
> > duration = time.time() - start
> > print(duration,'seconds')# 91.9426908493042 seconds
> >
> >
> > It took 92 seconds to get to the target start time. It does not only
> > apply to datetimes but for other purposes that uses "odometer-like"
> > patterns.
> >
> > I don't have any propose solution for now, but I guess adding this
> > feature within itertools will come in handy.
>
> Thank you for clarification. Now I understand your idea.
>
> For datetimes it is better to use the datetime classes:
>
> def iterdatetimes():
> delta = timedelta(microseconds=1)
> dt = datetime(2050,6,15,10,5,0)
> while True:
> yield dt
> dt += delta
>
> Note that in your example you missed 31th days, but iterate 29th and
> 30th February.
>
> See also the calendar module which provides date range iterators
> (although not with microsecond precision).
>
> Currently for general "odometer-like" patterns you can use the
> undocumented __setstate__ method of itertools.product. But this is on
> your own risk.
>
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