在Python字典中查找值的键:

my_dict = {'a': 1, 'b': 2, 'c': 3}

for key, value in my_dict.items():
    if value == 2:
        print(key)

my_dict = {'a': 1, 'b': 2, 'c': 3}

key = my_dict.get('b')
print(key)

my_dict = {'a': 1, 'b': 2, 'c': 3}

inverse_dict = {v: k for k, v in my_dict.items()}
key = inverse_dict.get(2)
print(key)