根据条件合并两个数据框

Question

I have these two dataframes:

sp_client 
     ConnectionID  Value
0     CN01493292    495
1     CN01492424    440
2     CN01491959    403
3     CN01493200    312
4     CN01493278    282
..           ...    ...
110   CN01492864      1
111   CN01492513      1
112   CN01492899      1
113   CN01493010      1
114   CN01493032      1
[115 rows x 2 columns]

sp_server 
     ConnectionID Value
1     CN01491920     2
1     CN01491920     2
3     CN01491922     2
3     CN01491922     2
5     CN01491928     2
..           ...   ...
595   CN01493166     3
595   CN01493166     3
595   CN01493166     3
597   CN01493163     2
597   CN01493163     2
[673 rows x 2 columns]

I would like to merge them in a way where sp_client['Value'] increments by addition of sp_sever['Value'] and sp_client['Value'] only when the rows satisfy the condition sp_sever['ConnectionID']==sp_client['ConnectionID'] .

It was a little bit complicated for me but I tried the following, but I am missing the condition part. Maybe it does not need to be merged in the first place. Happy to hear suggestions.

Answer 1

as per my comment, try to append tables and group them by ID while summing Value column as per example:

all_data = pd.concat([sp_server,sp_client])
all_data = all_data.groupby('ConnectionID')['Value'].agg(sum).reset_index()

out:

  ConnectionID  Value
0   CN01491920      4
1   CN01491922      4
2   CN01491928      2
3   CN01491959    403
4   CN01492424    440
5   CN01493200    312