Am I asking too much from datetime?

[thehaas]

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I'm trying to use the datetime module. The following seems to work
any day except the first day of the month:

import datetime
today = datetime.date.today()
print today 2004-06-01 yesterday = datetime.date(today.year, today.month, today.day-1)

Traceback (most recent call last):
File "<stdin>", line 1, in ?
ValueError: day is out of range for month

In other languages (specifically Java, but I'm sure these are others),
this would come out as "2004-05-31".

Is this is a bug, or outside of the functionality of datetime?
- --
Mike Hostetler
th*****@binary.net
http://www.binary.net/thehaas
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[Yermat]

th*****@binary.net wrote:

I'm trying to use the datetime module. The following seems to work
any day except the first day of the month:

import datetime
today = datetime.date.today()
print today
2004-06-01
yesterday = datetime.date(today.year, today.month, today.day-1)
Traceback (most recent call last):
File "<stdin>", line 1, in ?
ValueError: day is out of range for month

In other languages (specifically Java, but I'm sure these are others),
this would come out as "2004-05-31".

Is this is a bug, or outside of the functionality of datetime?
--
Mike Hostetler
th*****@binary.net
http://www.binary.net/thehaas

Of course it does not work !
0 is not a valid day...
You should do something like:

import datetime
today = datetime.date.today()
print today 2004-06-01 oneDay = datetime.timedelta(days=1)
print oneDay 1 day, 0:00:00 print today-oneDay

2004-05-31
--
Yermat

[Brian Quinlan]

>>>>yesterday = datetime.date(today.year, today.month, today.day-1)

Is this is a bug, or outside of the functionality of datetime?

Try writing it like this:

import datetime
today = datetime.date.today()
print today 2004-06-01 yesterday = today - datetime.timedelta(days=1)
print yesterday

2004-05-31

Cheers,
Brian

[thehaas]

Yermat <lo**@fejoz.net> wrote:

Of course it does not work !
0 is not a valid day...
You should do something like:

Except that it *does* work in other languages . . . that was part of
my point. Here's a sample from some working Java code:

// this works in January!
Calendar now = Calendar.getInstance();
Calendar lastmonth = Calendar.getInstance();
lastmonth.set(now.get(Calendar.YEAR),
now.get(Calendar.MONTH)-1,
now.get(Calendar.DATE));

>>> import datetime
>>> today = datetime.date.today()
>>> print today 2004-06-01 >>> oneDay = datetime.timedelta(days=1)
>>> print oneDay 1 day, 0:00:00 >>> print today-oneDay

2004-05-31

Got it. Cool -- thanks.
--
Mike Hostetler
th*****@binary.net
http://www.binary.net/thehaas

[Yermat]

th*****@binary.net wrote:

Yermat <lo**@fejoz.net> wrote:

[...]

Except that it *does* work in other languages . . . that was part of
my point. Here's a sample from some working Java code:
[...]

I understand your felling but I really believe it SHOULD not go that way
in other language... And so understand the python library point of view
to be the better one.

Anyway that's another debate ;-)

--
Yermat