Seymore4Head <Seymore4Head@Hotmail.invalid> writes: > This is not a new video, but it is new to me. > https://www.youtube.com/watch?v=-5wpm-gesOY > > Any links to some easy to follow time zone math?
The point of the video is that you should not do it yourself, use already written tools. It is quite comprehensive video. Here's how the mentioned issues could be resolved: - erratic UTC offset changes by politicians in different countries -- *use UTC timezone* for calculations, in addition (if necessary) store both the local time and timezone info. *Use pytz module* that provides access to the tz database to convert between timezones (many people get it wrong but it is not a rocket science). As said in the video, it won't help if the rules change a day before the DST transition but at least most [1] systems will be consistent. It also doesn't support some exotic timezone rules such as in Saudi Arabia (sunrise and/or sunset at the fixed local time every day [2]) or many timezones before 1970. - julian, gregorian calendars, proleptic UT (past dates): *use proleptic gregorian calendar (datetime module)* unless you know that you need otherwise (then you could investigate what JD means in a particular document given multiple possible interpretations) - leap seconds (posix, Mills, Windows(ntp), smear (google, java)), "right" timezones, and the difference between UT1, UTC(BIMP), GPS, TT(TAI), TCB, etc time scales: *ignore them* unless you know that you need otherwise e.g., legally elapsed seconds [3]. Here's some pictures to illustrate the difference between time scales [4]. [1] http://www.iana.org/time-zones/repository/tz-link.html [2] https://github.com/eggert/tz/blob/master/asia#L2439 [3] http://www.ucolick.org/~sla/leapsecs/epochtime.html [4] http://www.ucolick.org/~sla/leapsecs/deltat.html -- Akira -- https://mail.python.org/mailman/listinfo/python-list
