How to find common edges from a binary dataframe?

Question

This is my dataset:

Dept	Cell culture	Bioinfo	Immunology	Trigonometry	Algebra	Biotech	Optics
Biotech	1	1	1	0	0	1	0
Math	0	0	0	1	1	0	0
Physics	0	0	0	0	0	0	1

How I want my result:

Dept	0
Biotech	Cell culture
Biotech	Bioinfo
Biotech	Immunology
Math	Trigonometry
Math	Algebra
Physics	Optics

I need to form pairs that have the value one, but I also need to rid of those values which are the same in both column and row index - such as biotech here. Is there an easy way to do this?

Answer 1

Try this:

#df = df.set_index('Dept') if needed move dept into the index
df.dot(df.columns+',').str.strip(',').str.split(',').explode().reset_index()

Output:

      Dept             0
0  Biotech  Cell culture
1  Biotech       Bioinfo
2  Biotech    Immunology
3  Biotech       Biotech
4     Math  Trigonometry
5     Math       Algebra
6  Physics        Optics