| msg61219 - (view) |
Author: Michael Toews (mwtoews) |
Date: 2006-02-22 02:58 |
| My first request is relatively simple: add a 'yday' method to datetime.date and datetime.datetime. Thus I could do: >>> from datetime import * >>> t = date.today() >>> t.yday() 52 # rather than the less readable: >>> t.timetuple()[7] 52 # or worse: >>> int(t.strftime('%j')) 52 The second request is to have more alternate constructors for date or datetime objects. There are currently: * date(year,month,day) * date.fromtimestamp(timestamp) * date.fromordinal(ordinal) * date.today() I would like to have: * date.fromtimetuple(9-item time tuple structure) * date.strptime(data_string,format) As well, it would be nice to change: * date(year,month=None,day=None,yday=None) e.g.,: >>> date(2006,2,21) == date(2006,yday=52) True Here, a date can be formed from a year, month and day or from just the year and the day of the year, otherwise I have to convert using: >>> import time >>> year = 2006 >>> yday = 52 >>> t = time.strptime(`year`+'-'+`yday`,'%Y-%j') >>> datetime.date(t.tm_year,t.tm_mon,t.tm_mday) datetime.date(2006, 2, 21) If a safer approach is desired (as to not change the class constructor too much), then please offer an alternate, say: * date.fromyday(year,yday) or something like that. Thanks. +mt |
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| msg90720 - (view) |
Author: Jubaraj Borgohain (jborgohain) |
Date: 2009-07-20 01:46 |
| I have completed the following two new features for the datetime module (the changes are attached as a patch): a. Added a method yday() b. Added date.fromyday(year,yday), which returns a date object. The other features requested are already available. The tests for these two new features have also been added to test_datetimemodule.py. The patch has been only tested on trunk.(Python 2.7) |
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| msg91309 - (view) |
Author: Antoine Pitrou (pitrou) *  |
Date: 2009-08-05 10:52 |
| Some comments: - since there is already a weekday() method, the new method should be called yearday() rather than yday() - ditto for fromyday(): fromyearday() would be better - Modules/datetimemodule.c should only be indented with tabs, but your patch indents it with spaces in some places - the algorithm in date_fromyday() looks suboptimal: if you repeatedly call days_in_month(), you shouldn't have to call days_before_month() at the end, you can compute it by yourself I haven't tested the patch yet. Marc-André, do you have any take on the principle of this? |
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| msg91313 - (view) |
Author: Marc-Andre Lemburg (lemburg) * |
Date: 2009-08-05 11:06 |
| Antoine Pitrou wrote: > > Antoine Pitrou <pitrou@free.fr> added the comment: > > Some comments: > - since there is already a weekday() method, the new method should be > called yearday() rather than yday() > - ditto for fromyday(): fromyearday() would be better > - Modules/datetimemodule.c should only be indented with tabs, but your > patch indents it with spaces in some places > - the algorithm in date_fromyday() looks suboptimal: if you repeatedly > call days_in_month(), you shouldn't have to call days_before_month() at > the end, you can compute it by yourself > > I haven't tested the patch yet. > > Marc-André, do you have any take on the principle of this? mxDateTime uses attributes for such things, ie. .day_of_week, .day_of_year, .days_in_month. No idea, why the datetime module chose to implement access to this static information as method. I've never had a request for a way to construct a date by giving the year and day of the year - probably because it's just too easy to do by hand: 217 >>> Date(2009, 1, 1) + (217 - 1) <mx.DateTime.DateTime object for '2009-08-05 00:00:00.00' at 2b5320c262f0> |
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| msg91314 - (view) |
Author: Marc-Andre Lemburg (lemburg) * |
Date: 2009-08-05 11:09 |
| Hmm, looks like there's a bug in roundup's email interface... the code snippet should have read: >>> from mx.DateTime import * >>> today().day_of_year 217 >>> Date(2009, 1, 1) + (217 - 1) <mx.DateTime.DateTime object for '2009-08-05 00:00:00.00' at 2b5320c262f0> |
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| msg106206 - (view) |
Author: Alexander Belopolsky (belopolsky) * |
Date: 2010-05-20 23:17 |
| I think this should be rejected. The OP's premise was that t.timetuple()[7] was unreadable, but in the modern python, the same can be written as t.timetuple().tm_yday. The later is only slightly less readable than the proposed t.yday(). For the other half of the proposal, Marc-Andre's mxDate code translates into only slightly more complicated stdlib datetime code: def date_fromyday(year, yday): return date(year, 1, 1) + timedelta(yday - 1) |
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| msg106207 - (view) |
Author: Antoine Pitrou (pitrou) * |
Date: 2010-05-20 23:27 |
| > I think this should be rejected. The OP's premise was that > t.timetuple()[7] was unreadable, but in the modern python, the same > can be written as t.timetuple().tm_yday. Could I suggest such example be added to the documentation, though? The datetime / time jungle is difficult to navigate through, and I think for most people it is not obvious that the answer to their needs is to look at one of the attributes of the timetuple() result... |
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| msg106258 - (view) |
Author: Alexander Belopolsky (belopolsky) * |
Date: 2010-05-21 19:58 |
| On Thu, May 20, 2010 at 7:27 PM, Antoine Pitrou <report@bugs.python.org> wrote: > >> .. The OP's premise was that >> t.timetuple()[7] was unreadable, but in the modern python, the same >> can be written as t.timetuple().tm_yday. > > Could I suggest such example be added to the documentation, though? The documentation for timetuple method [1, 2] already contains a recipe for computing yday which is more efficient than t.timetuple().tm_yday: yday = d.toordinal() - date(d.year, 1, 1).toordinal() + 1 Maybe it can be improved by making it discoverable in searches for yday: """ ... is equivalent to time.struct_time((d.year, d.month, d.day, d.hour, d.minute, d.second, d.weekday(), yday, dst)), where yday = d.toordinal() - date(d.year, 1, 1).toordinal() + 1 is the day number of the year starting from 1 for January 1st. """ [1] http://docs.python.org/py3k/library/datetime.html#datetime.date.timetuple [2] http://docs.python.org/py3k/library/datetime.html#datetime.datetime.timetuple |
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| msg106288 - (view) |
Author: Georg Brandl (georg.brandl) * |
Date: 2010-05-22 08:21 |
| Care to suggest a patch? |
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| msg106338 - (view) |
Author: Alexander Belopolsky (belopolsky) * |
Date: 2010-05-23 17:16 |
| Attaching a documentation patch. |
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| msg106341 - (view) |
Author: Georg Brandl (georg.brandl) * |
Date: 2010-05-23 21:55 |
| Committed in r81489. Thanks! |
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