我导入了这个库,但没有报错 from pandas_datareader import data as pdr import datetime as dt start_date = dt.datetime(2021, 1, 1) end_date = dt.datetime(2021, 12, 31) df = pdr.get_data_yahoo('AAPL', start=start_date, end=end_date) print(df.head()) python pandas pandas-datareader...