How to Reverse Keys and Values in a Dictionary

# Original dictionary.
d = {"a": 1, "b": 2, "c": 3}
# Dictionary with keys exchanged with values.
d2 = {v: k for k, v in d.items()}
print(d2)  # {1: 'a', 2: 'b', 3: 'c'}

# No need to create a copy.
d = {v: k for k, v in d.items()}