Panda to_datetime 发出警告：tzname CET 已识别但未理解

Question

我有一个 pandas DataFrame，其列包含以下形式的字符串时间戳：

31 Jan 2020 17:29:37 CET

09 Apr 2021 15:34:53 CEST

将列转换为时间戳会返回警告：

df['timestamp'] = pd.to_datetime(df["timestamp"])
c:\Users\user\Miniconda3\lib\site-packages\dateutil\parser\_parser.py:1213: UnknownTimezoneWarning: tzname CET identified but not understood.  Pass `tzinfos` argument in order to correctly return a timezone-aware datetime.  In a future version, this will raise an exception.
  warnings.warn("tzname {tzname} identified but not understood.  "
c:\Users\user\Miniconda3\lib\site-packages\dateutil\parser\_parser.py:1213: UnknownTimezoneWarning: tzname CEST identified but not understood.  Pass `tzinfos` argument in order to correctly return a timezone-aware datetime.  In a future version, this will raise an exception.
  warnings.warn("tzname {tzname} identified but not understood.  "

我看过很多关于此警告的讨论，但在 pandas 方法的上下文中找不到解决方案to_datetime()。有人可以帮忙吗？准确规范化时间戳至关重要，因为我随后想使用此列对数据帧进行排序。

谢谢！

Answer 1

也许最有效的方法是只删除时区缩写，解析为日期时间并本地化到正确的时区：

import pandas as pd
df = pd.DataFrame({'datetime': ["31 Jan 2020 17:29:37 CET",
                                "09 Apr 2021 15:34:53 CEST"]})

df['datetime'] = df['datetime'].str.replace('CET|CEST', '', regex=True)
df['datetime'] = pd.to_datetime(df['datetime']).dt.tz_localize('Europe/Berlin')

df['datetime']
0   2020-01-31 17:29:37+01:00
1   2021-04-09 15:34:53+02:00
Name: datetime, dtype: datetime64[ns, Europe/Berlin]

或者您也可以在此处使用dateutil的解析器，但仅使用apply. 如果您有来自多个时区的数据（不仅是 CET/CEST），这尤其有用：

import pandas as pd
import dateutil

df = pd.DataFrame({'datetime': ["31 Jan 2020 17:29:37 CET",
                                "09 Apr 2021 15:34:53 CEST"]})

# define a 'real' time zone for each abbreviation:
tzmapping = {'CET': dateutil.tz.gettz('Europe/Berlin'),
             'CEST': dateutil.tz.gettz('Europe/Berlin')}

df['datetime'] = df['datetime'].apply(dateutil.parser.parse, tzinfos=tzmapping)

df['datetime']
0   2020-01-31 17:29:37+01:00
1   2021-04-09 15:34:53+02:00
Name: datetime, dtype: datetime64[ns, tzfile('/usr/share/zoneinfo/Europe/Berlin')]