[Python-Dev] proposal: add basic time type to the standard library (original) (raw)

M.-A. Lemburg mal@lemburg.com
Tue, 26 Feb 2002 22:26:47 +0100

Guido van Rossum wrote:

> > The timetuple() method provides access to all of these > > simultaneously. Isn't that enough? > > From a minimalist point of view, yet, but from a usability point > of view, no. > > > t.year() could be spelled as > > t.timetuple()[0]. > > Yes, but t.year() is a lot more readable. When do you ever use this in isolation? I'd expect in 99% of the cases you hand it off to a formatting routine, and guess what -- strftime() takes a time tuple.

FWIW, mxDateTime exposes these values as attributes -- there is no call overhead.

I worry about the time wasted by calling all of t.year(), t.month(), t.day() (etc.) -- given that they do so little, the call overhead is probably near 100%.

I wonder how often this is needed. The only occurrences of year() in the entire Zope source that I found are in various test routines.

I actually use the attributes quite a bit in my stuff and hardly ever use .strftime(). The mxDateTime is different though, e.g. I sometimes get questions about how to make strftime() output fractions of a seconds (doesn't work, because strftime() doesn't support it).

> > I expect that usually you'd request several of > > these together anyway, in order to do some fancy formatting, so the > > timetuple() approach makes sense. > > I find the time tuples to be really inconvenient. I always > have to slice off the parts I don't want, which I find annoying.

Serious question: what do you tend to do with time values? I imagine that once we change strftime() to accept an abstract time object, you'll never need to call either timetuple() or year() -- strftime() will do it for you.

Depends on the application space. Database applications will call .timetuple() very often and use strftime() hardly ever.

> > > with date parts > > > being one based and time parts being zero based. > > > > I'm not sure what you mean here. > > Years, months, and days should start from 1. > Hours, minutes and seconds should start from 0. > > One confusion I often have with time tuples is that I know > too much about C's time struct, which numbers months from 0 > and which has years since 1900.

I guess that confusion is yours alone. In Python, of course month and day start from 1. Whether years start from 1 is a theological question. :-)

It's not really a question: the year 0 simply does not exist in reality ! (Christians didn't have a 0 available at the time ;-)

Still, historic dates are usually referenced by making year 0 == 1 b.c., -1 == 2 b.c., etc.

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