Re: pytz has so many timezones!

On Oct 8, 5:48 pm, "J. Cliff Dyer" <j...@xxxxxxxxxxxxxxxx> wrote:
On 10/8/07, *J. Clifford Dyer* <j...@xxxxxxxxxxxxxxxx

<mailto:j...@xxxxxxxxxxxxxxxx>> wrote:

On Mon, Oct 08, 2007 at 01:13:24PM -0700, mensana...@xxxxxxx
<mailto:mensana...@xxxxxxx> wrote regarding Re: pytz has so many
timezones!:
>
> On Oct 8, 1:03 pm, Carsten Haese < cars...@xxxxxxxxxxx
<mailto:cars...@xxxxxxxxxxx>> wrote:
> > On Mon, 2007-10-08 at 10:41 -0700, mensana...@xxxxxxx
<mailto:mensana...@xxxxxxx> wrote:
> > > For example, Windows has seperate listings for
> >
> > > Central America
> > > Central Time (US & Canada)
> > > Guadalahara, Mexico City, Monterry - New
> > > Guadalahara, Mexico City, Monterry - Old
> > > Saskatchewan
> >
> > > but they are all GMT-6
> >
> > But they could have different rules for Daylight Saving Time.
>
> Which only matters if you're setting your clock.
>

Maybe this is where I'm not understanding you: Do you have another
use for setting a timezone? The only thing a time zone does, as far
as I can tell, is set clocks relative to a shared conception of time.

--
http://mail.python.org/mailman/listinfo/python-list





How about a calendar entry: I've got six people in places all over the
world to get on the phone together. If the app doesn't know their
notion of a time zone, that will never happen.

How about financial transactions: time-stamping transactions that move
around the world seems pretty useful to me. How do I know when said
transaction started if I can't convert the user's time into the
server's time?

Timezone is just another localization setting. It is no different
than language or keyboard layout. It is a piece of data that
describes the "world" the user lives in. Unfortunately, DST makes
them very complex because DST is determined by the country and can
change from year to year. I think the US' DST change this year had
more of a real-world impact than Y2K (of course, people actually
planned for Y2K, but that is a different story :).

tj

OK. Those all make sense, but I think they contradict mensanator's
statement that DST and half-hour offsets "only matter[] if you're
setting your clock." None of those are meaningful with 25 generic time
zones, which was what I was trying to understand. Under what normal
circumstances (outside of the US military creating an approximation for
their own internal usage) could 25 tzs be a useful abstraction?

It's how the world goes around.

Some people can't see the forest for the trees.

Is it obvious from all this timezone crap that

- a day lasts 48 hours?

- it can never be the same day everywhere in the world
simultaneously?

Isn't that just as important for worldwide transactions
as Daylight Savings Time (or lack thereof)?

Perhaps, once the basics
<http://members.aol.com/rotanasnem/truth/eykw_t40.htm>
are understood, the details won't be so confusing.


Cheers,
Cliff

.

Relevant Pages

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