在日期时间列上合并 pandas

Question

I have two dataframes like the following:

date                B
2017-01-03 01:00    0.017
2017-01-04 02:55    0.024
2017-01-05 16:53    -0.01
2017-01-06 10:22    0.024



date                A
2017-01-03 01:00    0.018
2017-01-06 09:16    -0.02

I would need to transform then to a one dataframe like that:

date                A       B
2017-01-03 01:00    0.018   0.017
2017-01-04 02:55            0.024
2017-01-05 16:53            -0.01
2017-01-06 09:16    -0.02
2017-01-06 10:22            0.024

How can I get it?

Answer 1

naming df2 as the dataframe that contains column A, and df1 as the dataframe that contains column B

Use DataFrame.merge :

df2.merge(df1,on='date',how='outer',sort=True)

Output:

             date      A      B
0 2017-01-03 01:00:00  0.018  0.017
1 2017-01-04 02:55:00    NaN  0.024
2 2017-01-05 16:53:00    NaN -0.010
3 2017-01-06 09:16:00 -0.020    NaN
4 2017-01-06 10:22:00    NaN  0.024