尝试使用Jupyter Notebook上的Pandas从现有列创建新列时出现NoneType错误

Question

所以我最近尝试开始使用Jupyter笔记本，因为我发现它们比在代码文件中保留冗长的注释要方便得多。

据说是为了测试基本功能，我想模拟移动平均线。但是，正如标题所述，我什至无法使用Pandas索引方法创建新列（该方法对我有用）。

这是我使用的代码：

import pandas as pd
from pandas_datareader import data as pdr
import matplotlib.pyplot as plt
from datetime import datetime
%matplotlib inline

fb = pdr.DataReader("FB","yahoo",datetime(2012,5,12),datetime(2020,5,25))
fb['MA10'] = fb['Close'].rolling(10).mean()

最后一行是产生错误（TypeError: 'NoneType' object is not iterable）的原因，该错误源于我调用fb['MA10']的原因，因为我在运行代码的右侧没有遇到任何问题。我很沮丧，希望收到任何反馈，我已经在下面张贴了完整的Error Traceback，供有兴趣的人使用。

--------------------------------------------------------
TypeError              Traceback (most recent call last)
<ipython-input-55-fa34c8084387> in <module>
      1 fb = pdr.DataReader("FB","yahoo",datetime(2012,5,12),datetime(2020,5,25))
----> 2 type(fb['MA10'])

c:\users\robjr\appdata\local\programs\python\python38\lib\site-packages\pandas\core\frame.py in __getitem__(self, key)
   2777 
   2778         # Do we have a slicer (on rows)?
-> 2779         indexer = convert_to_index_sliceable(self, key)
   2780         if indexer is not None:
   2781             # either we have a slice or we have a string that can be converted

c:\users\robjr\appdata\local\programs\python\python38\lib\site-packages\pandas\core\indexing.py in convert_to_index_sliceable(obj, key)
   2276         if idx._supports_partial_string_indexing:
   2277             try:
-> 2278                 return idx._get_string_slice(key)
   2279             except (KeyError, ValueError, NotImplementedError):
   2280                 return None

c:\users\robjr\appdata\local\programs\python\python38\lib\site-packages\pandas\core\indexes\datetimes.py in _get_string_slice(self, key, use_lhs, use_rhs)
    776     def _get_string_slice(self, key: str, use_lhs: bool = True, use_rhs: bool = True):
    777         freq = getattr(self, "freqstr", getattr(self, "inferred_freq", None))
--> 778         _, parsed, reso = parsing.parse_time_string(key, freq)
    779         loc = self._partial_date_slice(reso, parsed, use_lhs=use_lhs, use_rhs=use_rhs)
    780         return loc

pandas\_libs\tslibs\parsing.pyx in pandas._libs.tslibs.parsing.parse_time_string()

pandas\_libs\tslibs\parsing.pyx in pandas._libs.tslibs.parsing.parse_datetime_string_with_reso()

pandas\_libs\tslibs\parsing.pyx in pandas._libs.tslibs.parsing.dateutil_parse()

TypeError: 'NoneType' object is not iterable

Answer 1

您需要处理缺失的值，请尝试

fb['MA10'] = fb['Close'].fillna(0).rolling(10).mean()