Combining two columns as a nested list of tuples by category | python dataframe

Assume I have a dataframe: df = pd.DataFrame({"cat":["a",'a', 'b', 'c'],"A":[5, 6, 1, 4],"B":[7,8, 12, 5]})
which looks like this:

   cat  A   B
0   a   5   7
1   a   6   8
2   b   1   12
3   c   4   5

Now I want to combine column A and B based on column cat. If row['cat'] is the same, then combine row['A'] and row['B'] to list of tuples. So the above example’s desired output is: [[(5, 7), (6, 8)], [(1, 12)], [(4, 5)]]

Anyone knows how to do this?
Thank you in advance!

>Solution :

x = df.groupby('cat').apply(lambda x: list(zip(x['A'], x['B'])))

This gives you a series of this form:

cat
a    [(5, 7), (6, 8)]
b           [(1, 12)]
c            [(4, 5)]
dtype: object

You can do x.to_list() to get a list like in example output.