Problem with datetime #4557

Gurdil · 2015-06-26T07:27:54Z

from matplotlib import pyplot as plt
from datetime import datetime

datetime.strptime("Sep", '%b')

throw an exception :
Traceback (most recent call last):
File "/home/workspace/python/ephemeride/t.py", line 10, in
datetime.strptime("Sep", '%b')
File "/usr/lib/python3.4/_strptime.py", line 500, in _strptime_datetime
tt, fraction = _strptime(data_string, format)
File "/usr/lib/python3.4/_strptime.py", line 337, in _strptime
(data_string, format))
ValueError: time data 'Sep' does not match format '%b'

The exception doesn't occur if the matplotlib is not imported.
python 3.4.2/Ubuntu 14.10

tacaswell · 2015-06-26T16:03:13Z

I can not reproduce this.

dd_3k) ✔ ~ 
11:57 $ python
Python 3.4.3 |Continuum Analytics, Inc.| (default, Jun  4 2015, 15:29:08) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from datetime import datetime
>>> datetime.strptime("Sep", '%b')
datetime.datetime(1900, 9, 1, 0, 0)
>>> 
>>> 
(dd_3k) ✔ ~ 
11:57 $ 
(dd_3k) ✔ ~ 
11:57 $ python
Python 3.4.3 |Continuum Analytics, Inc.| (default, Jun  4 2015, 15:29:08) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from matplotlib import pyplot as plt
>>> from datetime import datetime
>>> datetime.strptime("Sep", '%b')
datetime.datetime(1900, 9, 1, 0, 0)
>>>

Does

>>> import datetime
>>> datetime.__file__

give you the same result in both cases?

what version of mpl are you using and how did you install it?

WeatherGod · 2015-06-26T16:08:47Z

perhaps this is a locale issue?

On Fri, Jun 26, 2015 at 12:03 PM, Thomas A Caswell <notifications@github.com

wrote:

I can not reproduce this.

dd_3k) ✔ ~
11:57 $ python
Python 3.4.3 |Continuum Analytics, Inc.| (default, Jun 4 2015, 15:29:08)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.

from datetime import datetime
datetime.strptime("Sep", '%b')
datetime.datetime(1900, 9, 1, 0, 0)

(dd_3k) ✔ ~
11:57 $
(dd_3k) ✔ ~
11:57 $ python
Python 3.4.3 |Continuum Analytics, Inc.| (default, Jun 4 2015, 15:29:08)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
from matplotlib import pyplot as plt
from datetime import datetime
datetime.strptime("Sep", '%b')
datetime.datetime(1900, 9, 1, 0, 0)

Does

import datetime
datetime.file

give you the same result in both cases?

what version of mpl are you using and how did you install ite?

—
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#4557 (comment)
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Gurdil · 2015-06-29T11:43:21Z

I install matplotlib through pip3

datetime.__file__

return in both case :
/usr/lib/python3.4/datetime.py

import matplotlib
print(matplotlib.__version__)
print(matplotlib.__file__)
print(matplotlib.get_configdir())

return :
1.4.3
/usr/local/lib/python3.4/dist-packages/matplotlib/init.py
/home/philip_j/.config/matplotlib

tacaswell · 2015-06-29T15:00:13Z

What is the native locale of your machine?

Gurdil · 2015-06-29T15:27:49Z

I'm not sure it's respond to the question but the command :

$ locale

return :

LANG=en_US.UTF-8
LANGUAGE=en_US
LC_CTYPE="en_US.UTF-8"
LC_NUMERIC=fr_FR.UTF-8
LC_TIME=fr_FR.UTF-8
LC_COLLATE="en_US.UTF-8"
LC_MONETARY=fr_FR.UTF-8
LC_MESSAGES="en_US.UTF-8"
LC_PAPER=fr_FR.UTF-8
LC_NAME=fr_FR.UTF-8
LC_ADDRESS=fr_FR.UTF-8
LC_TELEPHONE=fr_FR.UTF-8
LC_MEASUREMENT=fr_FR.UTF-8
LC_IDENTIFICATION=fr_FR.UTF-8
LC_ALL=

WeatherGod · 2015-06-29T15:30:46Z

On Mon, Jun 29, 2015 at 11:27 AM, Jean-Baptiste PHILIPPE <
notifications@github.com> wrote:

LC_TIME=fr_FR.UTF-8

Could you try the french word for September? LC_TIME indicates that it is
set to French.

tacaswell · 2015-06-29T15:31:14Z

Do the French month abbreviations work after you import matplotlib? My guess as to what is happening is that mpl is inspecting the LC envs and updating something on the python side.

Can you get the same error from just importing dateutil?

Gurdil · 2015-06-30T07:48:42Z

I test with 'Sep' because I assume it's the same in french(Septembre) and English(September).
The doc seem to only make an exception for Dutch:
https://docs.python.org/3.4/library/datetime.html#strftime-and-strptime-behavior

dateutil seem to work fine:

>>> from matplotlib import pyplot as plt
>>> from dateutil.parser import *
>>> print(parse("Sep"))
2015-09-30 00:00:00

tacaswell · 2015-07-01T15:49:01Z

The documentation reads to me like it is just using an example for Dutch.

What does

datetime.strptime("Sep", '%b')
import locale
datetime.strptime("Sep", '%b')

do on your system?

tacaswell · 2015-07-01T16:30:45Z

This looks like things working correctly, but not in the way you expect.

In [1]: import locale                                  

In [2]: from datetime import datetime                  

In [3]: datetime.strptime("Sep", '%b')         
Out[3]: datetime.datetime(1900, 9, 1, 0, 0)

In [4]: locale.setlocale(locale.LC_TIME, 'fr_FR.UTF-8')
Out[4]: 'fr_FR.UTF-8'

In [5]: datetime.strptime("Sep", '%b')                 
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-5-2fa518be5c22> in <module>()
----> 1 datetime.strptime("Sep", '%b')

/home/tcaswell/.virtualenvs/dd_3k/lib/python3.4/_strptime.py in _strptime_datetime(cls, data_string, format)
    498     """Return a class cls instance based on the input string and the
    499     format string."""
--> 500     tt, fraction = _strptime(data_string, format)
    501     tzname, gmtoff = tt[-2:]
    502     args = tt[:6] + (fraction,)

/home/tcaswell/.virtualenvs/dd_3k/lib/python3.4/_strptime.py in _strptime(data_string, format)
    335     if not found:
    336         raise ValueError("time data %r does not match format %r" %
--> 337                          (data_string, format))
    338     if len(data_string) != found.end():
    339         raise ValueError("unconverted data remains: %s" %

ValueError: time data 'Sep' does not match format '%b'

(to get this to run I had to generate the French locale files on my system)

It looks like in the top-level __init__.py there is a check if the rcparam 'axes.formatter.use_locale' is true (https://github.com/matplotlib/matplotlib/blob/master/lib/matplotlib/__init__.py#L1126) which calls locale.setlocale(local.LC_ALL, '') which queries the system to get the user set locale (https://docs.python.org/3.4/library/locale.html#locale.setlocale). By default this rcparam is False, my guess is you have this set to True on your machine?

ex

12:20 $ LC_TIME=fr_FR.UTF-8 python
Python 3.4.3 |Continuum Analytics, Inc.| (default, Jun  4 2015, 15:29:08) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.         
>>> from datetime import datetime
>>> datetime.strptime("Sep", '%b')
datetime.datetime(1900, 9, 1, 0, 0)
>>> import locale
>>> locale.setlocale(locale.LC_ALL, '')
'LC_CTYPE=en_US.UTF-8;LC_NUMERIC=en_US.UTF-8;LC_TIME=fr_FR.UTF-8;LC_COLLATE=en_US.UTF-8;LC_MONETARY=en_US.UTF-8;LC_MESSAGES=en_US.UTF-8;LC_PAPER=en_US.UTF-8;LC_NAME=en_US.UTF-8;LC_ADDRESS=en_US.UTF-8;LC_TELEPHONE=en_US.UTF-8;LC_MEASUREMENT=en_US.UTF-8;LC_IDENTIFICATION=en_US.UTF-8'
>>> datetime.strptime("Sep", '%b')     
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/tcaswell/.virtualenvs/dd_3k/lib/python3.4/_strptime.py", line 500, in _strptime_datetime
    tt, fraction = _strptime(data_string, format)
  File "/home/tcaswell/.virtualenvs/dd_3k/lib/python3.4/_strptime.py", line 337, in _strptime
    (data_string, format))
ValueError: time data 'Sep' does not match format '%b'
>>>

If I set that rcparam to True I can reproduce this:

(dd_3k) ✔ ~ 
12:26 $ LC_TIME=fr_FR.UTF-8 python
Python 3.4.3 |Continuum Analytics, Inc.| (default, Jun  4 2015, 15:29:08) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from datetime import datetime
>>> datetime.strptime("Sep", '%b')     
datetime.datetime(1900, 9, 1, 0, 0)
>>> import matplotlib
>>> datetime.strptime("Sep", '%b')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/tcaswell/.virtualenvs/dd_3k/lib/python3.4/_strptime.py", line 500, in _strptime_datetime
    tt, fraction = _strptime(data_string, format)
  File "/home/tcaswell/.virtualenvs/dd_3k/lib/python3.4/_strptime.py", line 337, in _strptime
    (data_string, format))
ValueError: time data 'Sep' does not match format '%b'
>>> 
>>> datetime.now().strftime('%b')
'juil.'
>>>

I do not think this is a bug, I think this is the system behaving in the intended way (even if that way is a bit annoying). Note the flip side of this is that you get dates printed out in the locale you have set.

If you need to be able to parse dates in a given locale, see http://stackoverflow.com/questions/18593661/how-do-i-strftime-a-date-object-in-a-different-locale

tacaswell · 2015-07-01T16:31:45Z

Sorry that last message is rather rambling, I was sorting out out while I was writing.

Gurdil · 2015-07-02T08:53:20Z

Thank, now I understand.

from matplotlib import pyplot as plt
from datetime import datetime

for i in range(1,13):
    date = datetime.strptime(str(i), '%m')
    print(date.strftime('%b'))

give me my local month abbreviation:

janv.
févr.
mars
avril
mai
juin
juil.
août
sept.
oct.
nov.
déc.

But the rcparam 'axes.formatter.use_locale' don't seem to be guilty, here a dump of my rcparam :
https://gist.github.com/Gurdil/c25e4f4b46ed4ace4964

Anyway thank you for helping me to solve this problem and I learned some things about python. It's a good days.

tacaswell · 2015-07-02T17:20:19Z

Hm, something is using locale but I am not sure it is worth tracking down.

Closing this as there isn't a bug in MPL, just tricksy internationalization.

Kangomnawe · 2019-05-18T00:34:18Z

Anyone pls..

tacaswell · 2019-05-18T01:08:19Z

@Kangomnawe That should probably be reported against pandas as Matplotlib does not appear to be involved on what you posted.

tacaswell added this to the unassigned milestone Jun 26, 2015

tacaswell added the status: needs confirmation label Jun 26, 2015

tacaswell closed this as completed Jul 2, 2015

tacaswell removed the status: needs confirmation label May 18, 2019

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Problem with datetime #4557

Problem with datetime #4557

Gurdil commented Jun 26, 2015

tacaswell commented Jun 26, 2015

WeatherGod commented Jun 26, 2015

Gurdil commented Jun 29, 2015

tacaswell commented Jun 29, 2015

Gurdil commented Jun 29, 2015

WeatherGod commented Jun 29, 2015

tacaswell commented Jun 29, 2015

Gurdil commented Jun 30, 2015

tacaswell commented Jul 1, 2015

tacaswell commented Jul 1, 2015

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Gurdil commented Jul 2, 2015

tacaswell commented Jul 2, 2015

Kangomnawe commented May 18, 2019

tacaswell commented May 18, 2019

Problem with datetime #4557

Problem with datetime #4557

Comments

Gurdil commented Jun 26, 2015

tacaswell commented Jun 26, 2015

WeatherGod commented Jun 26, 2015

Gurdil commented Jun 29, 2015

tacaswell commented Jun 29, 2015

Gurdil commented Jun 29, 2015

WeatherGod commented Jun 29, 2015

tacaswell commented Jun 29, 2015

Gurdil commented Jun 30, 2015

tacaswell commented Jul 1, 2015

tacaswell commented Jul 1, 2015

tacaswell commented Jul 1, 2015

Gurdil commented Jul 2, 2015

tacaswell commented Jul 2, 2015

Kangomnawe commented May 18, 2019

tacaswell commented May 18, 2019