Python 如何在Pandas中基于第二个DatetimeIndex对数据帧进行子集？

我需要根据以下条件在多个数据间隔上子集一个数据帧：

• 间隔的长度是一个参数
• 间隔的开始日期时间由第二个数据帧索引给出

数据帧#1（其中间隔的实际数据为）

请注意，我们使用df2.index（5）中的所有日期作为（3）段时间间隔的参考，从时间“00:00:00”开始，我们在df1.Close中获得了数据

提前谢谢

                        Open     High      Low    Close
DateTime                                               
2011-01-02 00:00:00  1257.75  1257.75  1255.25  1256.00
2011-01-02 02:00:00  1257.50  1257.50  1256.25  1256.75
2011-01-02 04:00:00  1257.75  1257.75  1255.00  1255.25
.
.
.
2011-07-02 00:00:00  1333.00  1335.25  1325.25  1326.75
2011-07-02 02:00:00  1336.50  1338.75  1331.25  1331.50
2011-07-02 04:00:00  1335.75  1337.25  1334.00  1334.25  

<class 'pandas.tseries.index.DatetimeIndex'>
[2011-01-02 00:00:00, ..., 2011-07-02 04:00:00]
Length: 2180, Freq: 120T, Timezone: None

                          Num  
DateTime                                                                  
2011-02-10 00:00:00  0.005117  
2011-03-10 00:00:00 -0.010079 
2011-04-14 00:00:00 -0.002288 
2011-05-12 00:00:00 -0.014116  
2011-06-09 00:00:00 -0.000390 

<class 'pandas.tseries.index.DatetimeIndex'>
[2010-02-10, ..., 2011-06-09]
Length: 5, Freq: None, Timezone: None

2011-02-10 00:00:00  1256.00
2011-02-10 02:00:00  1256.75
2011-02-10 04:00:00  1255.25
2011-03-10 00:00:00        .
2011-03-10 02:00:00        .
2011-03-10 04:00:00        .
2011-04-14 00:00:00        .
2011-04-14 02:00:00        .
2011-04-14 04:00:00        .
2011-05-12 00:00:00        .
2011-05-12 02:00:00        .
2011-05-12 04:00:00        .
2011-06-09 00:00:00  1326.75
2011-06-09 02:00:00  1331.50
2011-06-09 04:00:00  1334.25