How to merge and compute two dataframes?

Looking for help in merging the following two data-frames.

df1:  key     mean    stddev  ---     -----   -------  key1    30          3  key2    40          4  key3    50          5    df2:  key     mean    stddev  ---     -----   -------  key2    70          7  key3    80          8  key4    90          9  

The above two dataframes need to be merged to produce three different results:

1. Rows that are in df1 but not in df2:          key      mean     stddev      ---      -----   -------      key1     30       3    2. Rows that are in both df1 and df2 (please see the new columns delta_mean(difference of mean), delta_stddev (difference of stddev)        key    mean_x   stddev   mean_y   stddev_y    delta_mean   delta_stddev      ---    -----   -------   ------   --------    ---------    -----------      key2    40          4     70       7            30          3      key3    50          5     80       8            30          3    3. Rows that are in df2 but  but not not in df1    key      mean   stddev  ---       -----   -------  key4     90          9  

https://stackoverflow.com/questions/65819619/how-to-merge-and-compute-two-dataframes January 21, 2021 at 08:34AM