python - 如何解决此 KeyError？

Question

我正在尝试使用 python 来构建一个金融投资组合优化的程序。我想出了一个关键错误：日期。这是发生关键错误的段：

#create a dataframe to store the adjusted close price of the stocks
df = pd.DataFrame()

#store the adjusted close price of the stock into the df
for stock in assets:
  df[stock] = web.DataReader(stock, data_source='yahoo', start= stockStartDate , end = today)['Adj Close']

---

这是错误消息：

KeyError                                  Traceback (most recent call last)
/usr/local/lib/python3.7/dist-packages/pandas/core/indexes/base.py in get_loc(self, key, method, tolerance)
   2897             try:
-> 2898                 return self._engine.get_loc(casted_key)
   2899             except KeyError as err:

pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_loc()

pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_loc()

pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

KeyError: 'Date'

上述异常是以下异常的直接原因：

KeyError                                  Traceback (most recent call last)
6 frames
/usr/local/lib/python3.7/dist-packages/pandas/core/indexes/base.py in get_loc(self, key, method, tolerance)
   2898                 return self._engine.get_loc(casted_key)
   2899             except KeyError as err:
-> 2900                 raise KeyError(key) from err
   2901 
   2902         if tolerance is not None:

标签： pythonpandasdataframe