来自pandas_datareader的连接数据

我试图创建一个数据帧,其中的列来自两个不同的数据帧。

import pandas as pd
import numpy as np
from statsmodels import api as sm
import pandas_datareader.data as web
import datetime
start = datetime.datetime(2016,12,2)
end = datetime.datetime.today()
df = web.get_data_yahoo(['F'], start, end)
df1 = web.get_data_yahoo(['^GSPC'], start, end)
df3 = pd.concat([df['Adj Close'], df1['Adj Close']])

带着这个我想得到 df3 包含[Adj Close]数据的两列。我得到的是:

    F   ^GSPC
Date        
2016-12-01  10.297861   NaN
2016-12-02  10.140451   NaN
2016-12-05  10.306145   NaN
2016-12-06  10.405562   NaN
2016-12-07  10.819797   NaN
... ... ...
2019-11-22  NaN 3110.290039
2019-11-25  NaN 3133.639893
2019-11-26  NaN 3140.520020
2019-11-27  NaN 3153.629883
2019-11-29  NaN 3140.979980
1508 rows × 2 columns

我需要做些什么来摆脱南人的价值观,为什么会这样?