On Mon, Aug 3, 2015 at 11:32 AM, Chris Barker - NOAA Federal <[email protected]> wrote: > I'm a bit confused about what the strict tzinfo object has to do with > leap seconds.
Here is another way to explain it. Suppose I want to know how many seconds passed from 2011-07-15T12:00 to (and not including) 2012-07-15T12:00. Well, simple: it's one year, which is 365 days which is 365*24 hours, which is ... >>> 365*24*60*60 31536000 Simple, but wrong - we forgot that 2012 is a leap year. Try again >>> from datetime import * >>> SECOND = timedelta(seconds=1) >>> (datetime(2012, 7, 15, 12) - datetime(2011, 7, 15, 12)) / SECOND 31622400.0 This is better, but what if we are in a location that stopped observing DST in 2012? This is what we want tzstrict to account for, but if we just account for DST, we will still be wrong g because there was a leap second added at the end of June 2012. Luckily the same mechanism can be used to account for that. Note that in answering this question, we did not have to know how to call the extra day in February, the extra hour in March or April or the extra second in June. All we needed was a mapping from the start and end point to some scale that is considered linear (UTC for most practical purposes or TAI for those who care.) _______________________________________________ Datetime-SIG mailing list [email protected] https://mail.python.org/mailman/listinfo/datetime-sig The PSF Code of Conduct applies to this mailing list: https://www.python.org/psf/codeofconduct/
