如何按特定日期条件合并 2 个 pandas 数据框的列？

Question

I have 2 Pandas dataframes. One of them has [2262 rows x 6 columns] and is of the following structure:- Dataframe Name is df_sat -

Date.       Col1.   Col2.......   Col6
2017-08-26  numeric values in these columns
2017-08-31
....
2018-10-30
2018-11-09

Another dataframe has timestamps at 10 minutes intervals with shape [30000x105] with the following structure

DateTime.   Col1.  Col2.......... Col105
2017-08-26 00:00:00.  numeric values in these columns
2017-08-31 00:10:00
...
2018-11-01 15:50:00

What I would like is to merge these 2 dataframes together based on the dates which they share, and in cases where the same date is not there in both (as df_sat is at less regular intervals), the preceding date may be considered for merging.

The expected output is

DateTime.   Col1.  Col2.......... Col105               Col1-6 from df_sat
2017-08-27 00:00:00.  numeric values in these columns   Use 2017-08-26
2017-08-27 00:10:00                                     Use 2017-08-26
...
2018-10-31 15:50:00                                     Use 2018-10-30