Concatenate distinct columns in two dataframes using pandas (and append similar columns)

Question

My question is closely related to Pandas Merge - How to avoid duplicating columns but not identical.

I want to concatenate the columns that are diff

Answer 1

Using concat with groupby and first:

pd.concat([df1, df2, df3], 1).groupby(level=0, axis=1).first()

   A  B  C  D  id name place  qty  unit
0  a  b  c  d   1  Tom    NY    2    10
1  a  b  c  d   2  Ron    TK    3    15
2  a  b  c  d   3  Don   Lon    5    90
3  a  b  c  d   4  Sam    Hk    4    49