Reverse / invert a dictionary mapping

Question

Given a dictionary like so:

my_map = {\'a\': 1, \'b\': 2}

How can one invert this map to get:

inv_map = {1: \'a\', 2: \'b\'         


        

Answer 1

Combination of list and dictionary comprehension. Can handle duplicate keys

{v:[i for i in d.keys() if d[i] == v ] for k,v in d.items()}