Python pandas dataframe merge 2 rows into one with keys

Question

I have 2 dataframe, each has a single row, with the same columns:

df1 = feat_1 feat_2 ... feat_n a b c d ... z
          A    B          N    1 2 3 4     9 

df2 = feat_1 feat_2 ... feat_n a b c d ... z
          A    B          N    5 6 1 8     3

feat_1.. feat_n are the same with the 2 rows and the other columns should be concatenated such that the new row will be:

new_df = feat_1 feat_2 ... feat_n a_1 a_2 b_1 b_2 c_1 c_2 d_1 d_2 ... z_1 z_2
          A    B             N     1   5   2   6   3   1   4   8       9   3

What is the best way to do it?

Answer 1

Just use the merge command:

new_df = pd.merge(df1, df2, how="inner", on =["feat_1", 'feat_2', 'feat_n'], suffixes=('_1','_2'))

Input:

df1
  feat_1 feat_2 feat_n  a  b
0      A      B      N  1  2

df2
  feat_1 feat_2 feat_n  a  b
0      A      B      N  3  4

Code:

new_df = pd.merge(df1, df2, how="inner", on =["feat_1", 'feat_2', 'feat_n'], suffixes=('_1','_2'))

Prints:

  feat_1 feat_2 feat_n  a_1  b_1  a_2  b_2
0      A      B      N    1    2    3    4