[Question] datetime.datetime from TimePoint?

[movermeyer]

Hey everyone 👋,

I just found out about this project and was hoping to add metomi/isodatetime to ciso8601's parser benchmarks.

Is there a way to get a datetime.datetime object from a TimePoint object?

(In my case, I'm trying to do an equivalency comparison with a datetime)

I took a quick look through this project's code, but was unsuccessful.

[MetRonnie]

Hi, I don't think we have a method for doing that, but there are a couple of ways of achieving it currently:

1. Converting to seconds since unix epoch

   >>> from metomi.isodatetime.data import TimePoint
   >>> import datetime
   >>> timepoint = TimePoint(year=2010, month_of_year=3, hour_of_day=10, time_zone_hour=-3)
   >>> secs = int(timepoint.get("seconds_since_unix_epoch"))
   >>> datetime.fromtimestamp(secs)
   datetime.datetime(2010, 3, 1, 13, 0)

   Caveat: This loses time zone info (but does convert to UTC).

2. Using strftime/strptime

   >>> dump_format = "%Y%m%dT%H%M%S%z"
   >>> tp_str = timepoint.strftime(dump_format)
   >>> datetime.strptime(tp_str, dump_format)
   datetime.datetime(2010, 3, 1, 10, 0, tzinfo=datetime.timezone(datetime.timedelta(days=-1, seconds=75600)))

   (I've no idea why the time zone ends up weirdly for this example, but 75600 seconds minus 1 day does equal -3 hours)

Note: the above applies to isodateime 2.0.2 (current version). In the next version (likely to be called isodatetime 2.1.0), the TimePoint.get() method is going away and you will have to do secs = timepoint.seconds_since_unix_epoch instead. The next version will also contain a number of significant bug fixes and TimePoints will no longer be mutable as they are in 2.0.2.

[movermeyer]

Thanks for the response. 👏

I ended up writing a quick and dirty comparison function, that works well enough for my use case (the use case has very relaxed requirements).