带有时区的pandas数据帧的to_csv错误

Question

The following code gives an error under the pandas 0.17 but work very well with the 0.16.2.

No problem with the to_pickle function but get an error with the to_csv .

Has someone a tip to deal with it ?

In[23]: new_index = pd.date_range('2015-01-01', '2015-12-31', freq = 'H', tz='Europe/Paris')
In[24]: df = pd.DataFrame({}, index = new_index)
In[25]: df['test'] = 1.
In[26]: df.to_pickle(r'test.h5')

In[27]: df.to_csv(r'test.csv')
Traceback (most recent call last):
  File "C:\Anaconda\lib\site-packages\IPython\core\interactiveshell.py", line 3035, in run_code
    exec(code_obj, self.user_global_ns, self.user_ns)
  File "<ipython-input-27-2ced74ae66e1>", line 1, in <module>
    df.to_csv(r'test.csv')
  File "C:\Anaconda\lib\site-packages\pandas\core\frame.py", line 1289, in to_csv
    formatter.save()
  File "C:\Anaconda\lib\site-packages\pandas\core\format.py", line 1494, in save
    self._save()
  File "C:\Anaconda\lib\site-packages\pandas\core\format.py", line 1594, in _save
    self._save_chunk(start_i, end_i)
  File "C:\Anaconda\lib\site-packages\pandas\core\format.py", line 1619, in _save_chunk
    quoting=self.quoting)
  File "C:\Anaconda\lib\site-packages\pandas\core\index.py", line 1292, in to_native_types
    return values._format_native_types(**kwargs)
  File "C:\Anaconda\lib\site-packages\pandas\tseries\index.py", line 746, in _format_native_types
    format = _get_format_datetime64_from_values(self, date_format)
  File "C:\Anaconda\lib\site-packages\pandas\core\format.py", line 2191, in _get_format_datetime64_from_values
    is_dates_only = _is_dates_only(values)
  File "C:\Anaconda\lib\site-packages\pandas\core\format.py", line 2145, in _is_dates_only
    values = DatetimeIndex(values)
  File "C:\Anaconda\lib\site-packages\pandas\util\decorators.py", line 89, in wrapper
    return func(*args, **kwargs)
  File "C:\Anaconda\lib\site-packages\pandas\tseries\index.py", line 344, in __new__
    ambiguous=ambiguous)
  File "pandas\tslib.pyx", line 3753, in pandas.tslib.tz_localize_to_utc (pandas\tslib.c:64516)
AmbiguousTimeError: Cannot infer dst time from Timestamp('2015-10-25 02:00:00'), try using the 'ambiguous' argument

Answer 1

This seems to be a known bug #11619 and should be fixed in 0.17.1

The underlying issue is that your timeframe crosses from standard time to daylight saving time, which is the exact time showing in the error AmbiguousTimeError: Cannot infer dst time from Timestamp('2015-10-25 02:00:00')