I have this dataframe:
Category 3,Chapter I,Chapter II,Chapter III
prima,126,97,83
da,38,24,24
sps.,22,17,18
How to make it like:
prima,126,Chapter I
prima, 97, Chapter II
prima, 83, Chapter III
da, 38, Chapter I
[...]
I have this dataframe:
Category 3,Chapter I,Chapter II,Chapter III
prima,126,97,83
da,38,24,24
sps.,22,17,18
How to make it like:
prima,126,Chapter I
prima, 97, Chapter II
prima, 83, Chapter III
da, 38, Chapter I
[...]
 
    
    You can run:
result = df.set_index('Category 3').stack().rename('Value').reset_index()
For your data sample the result is:
  Category 3      level_1  Value
0      prima    Chapter I    126
1      prima   Chapter II     97
2      prima  Chapter III     83
3         da    Chapter I     38
4         da   Chapter II     24
5         da  Chapter III     24
6       sps.    Chapter I     22
7       sps.   Chapter II     17
8       sps.  Chapter III     18
If you want, rename level_1 column to any meaningful name and change the order of columns.
