On Mon, Jun 4, 2012 at 11:46 AM, Alexander Belopolsky <alexander.belopol...@gmail.com> wrote: > On Mon, Jun 4, 2012 at 1:12 PM, Guido van Rossum <gu...@python.org> wrote: >> ... I heard >> a colleague complain that he'd lost several hours trying to figure out >> how to determine whether two datetimes were within 24h of each other, >> getting confused by what was happening when the two were on different >> sides of a DST transition (or worse, in the middle of one). > > I don't think this is a problem that a general purpose module such as > datetime can resolve. Assuming that all instances are timezone aware, > either of the following tests may be appropriate for a given > application: > > 1) dt1 - dt2 == timedelta(1) > > 2) dt1.date() - dt2.date() == timedelta(1) and dt1.time() == dt2.time() > > If your application deals with physical processes - (1) may be > appropriate, but if it deals with human schedules - (2) may be > appropriate.
You seem to have misread -- I don't want to check if they are exactly 24 hours apart. I want to check if they are at most 24 hours apart. The timezone can be assumed to be the same on dt1 and dt2. A variant of (1) was what was needed -- the user had just confused themselves into thinking they needed to convert to UTC first, and done a poor job of that. This is a common situation. > The only right solution is to lobby your government to abandon the DST. That's not helping. -- --Guido van Rossum (python.org/~guido) _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
