How to melt 2 columns at the same time?

Question

In Pandas, I have the following data frame:

   id1 id2 t1  l1  t2  l2 
0  1   2   a   b   c   d
1  3   4   g   h   i   j

I would like to me

Answer 1

This is wide_to_long

pd.wide_to_long(df,['t','l'],i=['id1','id2'],j='drop').reset_index(level=[0,1])
Out[52]: 
      id1  id2  t  l
drop                
1       1    2  a  b
2       1    2  c  d
1       3    4  g  h
2       3    4  i  j