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Created on 2015-03-20 11:19 by serhiy.storchaka, last changed 2022-04-11 14:58 by admin.
| Messages (6) | |||
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| msg238645 - (view) | Author: Serhiy Storchaka (serhiy.storchaka) *  |
Date: 2015-03-20 11:19 | |
strptime() with year-weekday pair can produce invalid data.
>>> time.strptime('2015 0', '%Y %w')
time.struct_time(tm_year=2015, tm_mon=1, tm_mday=1, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=6, tm_yday=1, tm_isdst=-1)
>>> time.strptime('2015 1', '%Y %w')
time.struct_time(tm_year=2015, tm_mon=1, tm_mday=1, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=0, tm_yday=1, tm_isdst=-1)
>>> time.strptime('2015 2', '%Y %w')
time.struct_time(tm_year=2015, tm_mon=1, tm_mday=1, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=1, tm_yday=1, tm_isdst=-1)
>>> time.strptime('2015 3', '%Y %w')
time.struct_time(tm_year=2015, tm_mon=1, tm_mday=1, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=2, tm_yday=1, tm_isdst=-1)
>>> time.strptime('2015 4', '%Y %w')
time.struct_time(tm_year=2015, tm_mon=1, tm_mday=1, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=3, tm_yday=1, tm_isdst=-1)
>>> time.strptime('2015 5', '%Y %w')
time.struct_time(tm_year=2015, tm_mon=1, tm_mday=1, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=4, tm_yday=1, tm_isdst=-1)
>>> time.strptime('2015 6', '%Y %w')
time.struct_time(tm_year=2015, tm_mon=1, tm_mday=1, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=5, tm_yday=1, tm_isdst=-1)
You get Jan 1 with any weekday.
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| msg238679 - (view) | Author: Skip Montanaro (skip.montanaro) *  |
Date: 2015-03-20 14:26 | |
I don't think this is a bug. From the 2.7.9 docs: The default values used to fill in any missing data when more accurate values cannot be inferred are (1900, 1, 1, 0, 0, 0, 0, 1, -1). |
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| msg238682 - (view) | Author: Serhiy Storchaka (serhiy.storchaka) * |
Date: 2015-03-20 14:36 | |
Actually you can got invalid data for any date.
>>> time.strptime('2015 3 20', '%Y %m %d')
time.struct_time(tm_year=2015, tm_mon=3, tm_mday=20, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=4, tm_yday=79, tm_isdst=-1)
>>> time.strptime('2015 3 20 0', '%Y %m %d %w')
time.struct_time(tm_year=2015, tm_mon=3, tm_mday=20, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=6, tm_yday=79, tm_isdst=-1)
All date values are known, the problem is that they contradict.
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| msg238695 - (view) | Author: Skip Montanaro (skip.montanaro) * |
Date: 2015-03-20 15:46 | |
>>>> time.strptime('2015 3 20 0', '%Y %m %d %w')
> time.struct_time(tm_year=2015, tm_mon=3, tm_mday=20, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=6, tm_yday=79, tm_isdst=-1)
>
> All date values are known, the problem is that they contradict.
Garbage in, garbage out. :-) Clearly today is not Sunday. I not sure
there is a correct answer in the face of contradictory inputs.
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| msg238702 - (view) | Author: Serhiy Storchaka (serhiy.storchaka) * |
Date: 2015-03-20 17:00 | |
Agree. But may be at least emit a warning? |
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| msg407340 - (view) | Author: Irit Katriel (iritkatriel) * |
Date: 2021-11-30 00:12 | |
Reproduced on 3.11. |
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| History | |||
|---|---|---|---|
| Date | User | Action | Args |
| 2022-04-11 14:58:14 | admin | set | github: 67905 |
| 2021-11-30 00:12:31 | iritkatriel | set | nosy:
+ iritkatriel messages: + msg407340 versions: + Python 3.9, Python 3.10, Python 3.11, - Python 2.7, Python 3.4, Python 3.5 |
| 2015-03-20 17:00:08 | serhiy.storchaka | set | messages: + msg238702 |
| 2015-03-20 15:46:48 | skip.montanaro | set | messages: + msg238695 |
| 2015-03-20 14:36:45 | serhiy.storchaka | set | messages: + msg238682 |
| 2015-03-20 14:26:18 | skip.montanaro | set | nosy:
+ skip.montanaro messages: + msg238679 |
| 2015-03-20 11:19:31 | serhiy.storchaka | create | |