-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 07/27/2015 09:36 PM, Tim Peters wrote: > So what do _you_ do with datetime arithmetic, Tres? Do you do > datetime calculations at all, or just store/retrieve values as-is? > If the former, are you disturbed that adding timedelta(hours=24) to > an aware datetime object never changes the time components (only the > day, and possibly also month, and possibly also year)? If that has > disturbed you, did you find a way to accomplish what you wanted > instead - or are you still stuck? ;-)
Sample use cases: - - Embargo a pre-prepared story until 8:00 AM US/Central next Monday. - - Likewise, but allow it to run for three weeks. - - Create a recurring event which occurs from 7:00 - 9:00 PM US/Eastern on the last Thursday of each month. - - Issue a bid for a commodity lot N days before its expiration date; update that bid (if another bid has occurred) at the same time each day until expiration. - - Mark messages published on a distributed event channel to allow clients to sequence them unambiguously. - - For a given sequence of events: if no subsequent matching event occurs within five calendar days of the last event in the sequence, issue a "resolved" event, terminating the sequence. - - The same, except define the interval using "business days" (including applying a user-defined holiday calendar). - - Measure / bucket widgets produced across multiple production lines by quarter / month / day / shift / hour, and generate reports comparing results week-over-week, quarter-over-quarter, etc. In none of those cases involving "days" was the "one day is 24 hours, exactly" a sufficient approximation, and none of them could tolerate naive datetimes. Typically, the application used a "date interval" object (or a recurrence object) which generated date offsets without assuming that a "day" was 86400 seconds. Tres. - -- =================================================================== Tres Seaver +1 540-429-0999 tsea...@palladion.com Palladion Software "Excellence by Design" http://palladion.com -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQIcBAEBAgAGBQJVt3ArAAoJEPKpaDSJE9HYfCcP/07RNZY6Vp5wfcR8wnv3Zk/Z 3SgaEWPIG7s8ysqUhcxT/E6pMdgrLDwSm681Ceh8SDFKdvmXIgSO4UXdsHz6X9Ja gffUk1p5m/A1p0GFdcIMN9EHI1Ligtrf/s0gYJ+b0TqiDUW9mpD1xOmQaNK2/eE4 xf3iYSdFgvcqNMlIzQ+AyzP53M9npv78zCqr/LI18mRczMOHENb98jXeWycIMHyV TbHL/cZ///Uj1IqAmydezj4K0biPwUeMsNeqzzuMbDsiVFdZn+rql9N+V4BuzINZ ivmvdEIFdBqFoRcJJyoWsuqaR8GX0i/2LTVgj4Xcustj1Wnh2Aq+2yUNi0DQvjxh Y79QbVPtPyjkzFUh/dZG5hLSAEWxXtbaFsinq1eN+hraBXHAN4sTdUeL1zGV7Pz5 SSQXwe2cabqALzjbpSiLN8gZ3s7DbcVn4uDLsS3L7iyoC5Y51puZut6ui+TmdbgK fG2zvkRNayOyiRa1vymNZsjiM9XYrNABVhuVdM+xgqCe62q+bcUKKVKRIZY1JWq4 Fh0hy9MVPeT51oFuaIAPQJfPKleSLf8xElHZ9M0Gm4PbJDvmr04AjZ7MHWicXsqR pbhlbfIDO8c2Pt7JfjLPGY/0UZi0ZVeJV8bD5EaM3xcn80DLKW9UL+8Yg4h9br59 RURP7/N6S66jAEHfcUFo =3LBp -----END PGP SIGNATURE----- _______________________________________________ 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
