[Python-Dev] ISO 8601 durations and datetime.timedelta
Andrew wrote: I meant ISO 8601 syntax for durations [1]. That's exactly what I was referring to. Consider this session: now = datetime.datetime.now() now datetime.datetime(2014, 3, 28, 12, 4, 38, 517110) then = now - datetime.timedelta(days=57, hours=12, minutes=12, seconds=12) now datetime.datetime(2014, 3, 28, 12, 4, 38, 517110) then datetime.datetime(2014, 1, 29, 23, 52, 26, 517110) so, the difference is: now - then datetime.timedelta(57, 43932) Given that the timedelta has more than a month's worth of days, how would you describe it using the ISO8601 duration notation without referencing a specific point in time? Conversely, given your example, P3Y6M4DT12H30M5S, how would you convert that into a timedelta without knowing which exact years and months this duration refers to? Timedelta objects are very precise beasts, which is almost certainly why they don't support years and months args in their constructors. This is why I said this deserved a separate topic. Probably on python-ideas. Skip ___ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] ISO 8601 durations and datetime.timedelta
On Fri, Mar 28, 2014 at 1:13 PM, Skip Montanaro s...@pobox.com wrote: Given that the timedelta has more than a month's worth of days, how would you describe it using the ISO8601 duration notation without referencing a specific point in time? Conversely, given your example, P3Y6M4DT12H30M5S, how would you convert that into a timedelta without knowing which exact years and months this duration refers to? Timedelta objects are very precise beasts, which is almost certainly why they don't support years and months args in their constructors. So why would they need to support them in str()? We could make str(timedelta(days=369, hours=12, minutes=30, seconds=5)) return P369DT12H30M5S, but that would hardly be an improvement over print timedelta(days=369, hours=12, minutes=30, seconds=5) 369 days, 12:30:05 and I don't think ISO 8601 allows for negative durations, so it gives us little guidance for the other issue either. My preference would be to leave strict ISO 8601 compliance to 3rd party libraries. ___ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
