python - Using column name as a new attribute in pandas

Question

I have the following data structure

Date         Agric  Food 
01/01/1990    1.3   0.9  
01/02/1990    1.2   0.9 

I would like to covert it into the format

Date        Sector  Beta
01/01/1990  Agric   1.3
01/02/1990  Agric   1.2
01/01/1990  Food    0.9
01/02/1990  Food    0.9

while I am sure I can do this in a complicated way, is there a way of doing this in a few line of code?

Answer 1

Use set_index and stack:

df.set_index('Date').rename_axis('Sector',axis=1).stack()
  .reset_index(name='Beta')

Output:

         Date Sector  Beta
0  01/01/1990  Agric   1.3
1  01/01/1990   Food   0.9
2  01/02/1990  Agric   1.2
3  01/02/1990   Food   0.9