Re: Add a month
Ok, 30 minutes later, here's my best solution. http://www.answermysearches.com/index.php/how-to-add-months-to-a-date-in-python/53/ (Posted on my website to make sure tabs are kept.) Would someone mind double-checking my logic before I put this into production next Tuesday? -Greg On 2/17/06, Gregory Piñero <[EMAIL PROTECTED]> wrote: > Actually, no wait, that's bad. It doesn't increment the year. > > Does anyone have a simple way to code this? > > -Greg > > > On 2/17/06, Gregory Piñero <[EMAIL PROTECTED]> wrote: > > Here's how I do it: > > > > def monthify(anint): > > if anint%12==0:return 12 > > else:return anint%12 > > > > import datetime > > d=datetime.datetime.today() > > dplus1month=datetime.datetime(d.year,monthify(d.month+1),d.day) > > > > We need monthify because adding 1 to 12 is bad otherwise! > > > > -Greg > > > > On 17 Feb 2006 04:15:39 -0800, Paul Boddie <[EMAIL PROTECTED]> wrote: > > > Fredrik Lundh wrote: > > > > > > > > what do you expect d_new to be after the operation ? if the answer > > > > is date(2006,3,17), what's date(2006,1,31) plus one month? > > > > > > February 31st, of course: > > > > > > http://sql-info.de/mysql/gotchas.html#1_14 > > > > > > ;-) > > > > > > Paul > > > > > > -- > > > http://mail.python.org/mailman/listinfo/python-list > > > > > > > > > -- > > Gregory Piñero > > Chief Innovation Officer > > Blended Technologies > > (www.blendedtechnologies.com) > > > > > -- > Gregory Piñero > Chief Innovation Officer > Blended Technologies > (www.blendedtechnologies.com) > -- Gregory Piñero Chief Innovation Officer Blended Technologies (www.blendedtechnologies.com) -- http://mail.python.org/mailman/listinfo/python-list
Re: Add a month
Paul Boddie napisał(a): >>what do you expect d_new to be after the operation ? if the answer >>is date(2006,3,17), what's date(2006,1,31) plus one month? > > February 31st, of course: > > http://sql-info.de/mysql/gotchas.html#1_14 MS SQL Server documentation marks dateadd() result as non-deterministic in Transact-SQL reference. Adding 1 month to jan 31st gives feb 28 or 29, depending on year. It's not that bad, providing you know this behaviour. ;) -- Jarek Zgoda http://jpa.berlios.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Add a month
On Fri, 2006-02-17 at 16:10, Gregory Piñero wrote: > Actually, no wait, that's bad. It doesn't increment the year. > > Does anyone have a simple way to code this? > > -Greg > > > On 2/17/06, Gregory Piñero <[EMAIL PROTECTED]> wrote: > > Here's how I do it: > > > > def monthify(anint): > > if anint%12==0:return 12 > > else:return anint%12 > > > > import datetime > > d=datetime.datetime.today() > > dplus1month=datetime.datetime(d.year,monthify(d.month+1),d.day) > > > > We need monthify because adding 1 to 12 is bad otherwise! > > > > -Greg > > > > On 17 Feb 2006 04:15:39 -0800, Paul Boddie <[EMAIL PROTECTED]> wrote: > > > Fredrik Lundh wrote: > > > > > > > > what do you expect d_new to be after the operation ? if the answer > > > > is date(2006,3,17), what's date(2006,1,31) plus one month? > > > > > > February 31st, of course: > > > > > > http://sql-info.de/mysql/gotchas.html#1_14 > > > > > > ;-) > > > > > > Paul > > > > > > -- > > > http://mail.python.org/mailman/listinfo/python-list > > > > > > > > > -- > > Gregory Piñero > > Chief Innovation Officer > > Blended Technologies > > (www.blendedtechnologies.com) > > > > I don't know if this qualifies as simple, but it seems to work: def addmonths(thedate,months): "Add months to ." import datetime y,m,d = thedate.timetuple()[:3] y2, m2 = divmod(m+months-1, 12) return datetime.date(y+y2,m2+1,d) Note that the date constructor will raise an exception if the result happens to be an invalid date such as February 30th or November 31st. -Carsten -- http://mail.python.org/mailman/listinfo/python-list
Re: Add a month
Actually, no wait, that's bad. It doesn't increment the year. Does anyone have a simple way to code this? -Greg On 2/17/06, Gregory Piñero <[EMAIL PROTECTED]> wrote: > Here's how I do it: > > def monthify(anint): > if anint%12==0:return 12 > else:return anint%12 > > import datetime > d=datetime.datetime.today() > dplus1month=datetime.datetime(d.year,monthify(d.month+1),d.day) > > We need monthify because adding 1 to 12 is bad otherwise! > > -Greg > > On 17 Feb 2006 04:15:39 -0800, Paul Boddie <[EMAIL PROTECTED]> wrote: > > Fredrik Lundh wrote: > > > > > > what do you expect d_new to be after the operation ? if the answer > > > is date(2006,3,17), what's date(2006,1,31) plus one month? > > > > February 31st, of course: > > > > http://sql-info.de/mysql/gotchas.html#1_14 > > > > ;-) > > > > Paul > > > > -- > > http://mail.python.org/mailman/listinfo/python-list > > > > > -- > Gregory Piñero > Chief Innovation Officer > Blended Technologies > (www.blendedtechnologies.com) > -- Gregory Piñero Chief Innovation Officer Blended Technologies (www.blendedtechnologies.com) -- http://mail.python.org/mailman/listinfo/python-list
Re: Add a month
Here's how I do it: def monthify(anint): if anint%12==0:return 12 else:return anint%12 import datetime d=datetime.datetime.today() dplus1month=datetime.datetime(d.year,monthify(d.month+1),d.day) We need monthify because adding 1 to 12 is bad otherwise! -Greg On 17 Feb 2006 04:15:39 -0800, Paul Boddie <[EMAIL PROTECTED]> wrote: > Fredrik Lundh wrote: > > > > what do you expect d_new to be after the operation ? if the answer > > is date(2006,3,17), what's date(2006,1,31) plus one month? > > February 31st, of course: > > http://sql-info.de/mysql/gotchas.html#1_14 > > ;-) > > Paul > > -- > http://mail.python.org/mailman/listinfo/python-list > -- Gregory Piñero Chief Innovation Officer Blended Technologies (www.blendedtechnologies.com) -- http://mail.python.org/mailman/listinfo/python-list
Re: Add a month
Fredrik Lundh wrote: > > what do you expect d_new to be after the operation ? if the answer > is date(2006,3,17), what's date(2006,1,31) plus one month? February 31st, of course: http://sql-info.de/mysql/gotchas.html#1_14 ;-) Paul -- http://mail.python.org/mailman/listinfo/python-list
Re: Add a month
Fredrik Lundh wrote: > [EMAIL PROTECTED] wrote: > >> Hi, this is probably a really simple question but... >> How do you add a month to a datetime date in python? It would be nice >> if you could do something like: >> >> d = datetime.date(2006,2,17) >> dm = datetime.timedelta(months=1) >> d_new = d + dm >> >> but timedelta doesn't have a 'months' setting. Am I missing some easy >> method or do I have to code a work around myself?? > > what do you expect d_new to be after the operation ? if the answer > is date(2006,3,17), what's date(2006,1,31) plus one month? Traceback (most recent call last): File "", line 1, in ? ValueError: date domain error in analogy to math.sqrt (-2) Daniel -- http://mail.python.org/mailman/listinfo/python-list
Re: Add a month
[EMAIL PROTECTED] wrote: > Hi, this is probably a really simple question but... > How do you add a month to a datetime date in python? It would be nice > if you could do something like: > > d = datetime.date(2006,2,17) > dm = datetime.timedelta(months=1) > d_new = d + dm > > but timedelta doesn't have a 'months' setting. Am I missing some easy > method or do I have to code a work around myself?? what do you expect d_new to be after the operation ? if the answer is date(2006,3,17), what's date(2006,1,31) plus one month? -- http://mail.python.org/mailman/listinfo/python-list
Re: Add a month
[EMAIL PROTECTED] > Hi, this is probably a really simple question but... > How do you add a month to a datetime date in python? It would be nice > if you could do something like: > > d = datetime.date(2006,2,17) > dm = datetime.timedelta(months=1) > d_new = d + dm > > but timedelta doesn't have a 'months' setting. Am I missing some easy > method or do I have to code a work around myself?? You need to code you own version. It was not included with datetime.timedelta() because the definition is ambiguous (i.e. what date is one month after Jan 30th?). Raymond -- http://mail.python.org/mailman/listinfo/python-list
Add a month
Hi, this is probably a really simple question but... How do you add a month to a datetime date in python? It would be nice if you could do something like: d = datetime.date(2006,2,17) dm = datetime.timedelta(months=1) d_new = d + dm but timedelta doesn't have a 'months' setting. Am I missing some easy method or do I have to code a work around myself?? Thanks in advance for the help! -- http://mail.python.org/mailman/listinfo/python-list
