On Tue, 6 Sep 2005, Rick Measham wrote:
So, assuming America/Chicago: (2003-12-01) - (2003-09-01) will return a
duration representing 2 months, 29 days and 23 hours?
Yes, _but_ the docs suggest that if you don't like this you probably
wanted _date_ math (not datetime) in the first place, and you can use
delta_md(), which will return 3 months.
If so, I'd prefer it returned a duration object representing n seconds ...
THEN I'd like to see another 'local difference' function that worked down
from years ..
2003 - 2003 = 0 years
12 - 09 = 3 months
01 - 01 = 0 days
(extending .. (2004-01-23) - (2003-09-01) becomes:
2004 - 2003 = 1 year \ auto normalises / 0 years
01 - 09 = -8 months >-- to get rid of --< 4 months
23 - 01 = 22 days / negative values \ 22 days
)
Examples that are date only are pretty meaningless. You can already get
the results you're suggesting with the delta_md() method. The
complication is when you add in times to the mix. Once you do that it
gets really messy, especially if you're trying to produce a duration that
consists of all positive or negative deltas.
Then again, I wonder if durations shouldn't be removed altogether and put
into separate packages that allowed people to choose their math assumptions.
You always suggest splitting it up into more packages, but that doesn't
necessarily help. I think the real problem here is that a lot of people
just want date math, and they don't care about times. The real split
should probably be a date-only module vs a date+time module.
-dave
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