__getitem__ __setitem__ __delitem__

# __getitem__ __setitem__ __delitem__
# 只适用于类似操作字典的操作才会触发
class Foo:
    def __getitem__(self, item):
        print('调用了__getitem__')
        return self.__dict__[item]

    def __setitem__(self, key, value):
        self.__dict__[key] = value
        print('调用了__setitem__')

    def __delitem__(self, key):
        self.__dict__.pop(key)
        print('调用了__delitem__')


f1 = Foo()

f1['name'] = 'alex'  # 调用了__setitem__
f1['age'] = 18  # 调用了__setitem__

f1['age']   # 调用了__getitem__

print(f1.__dict__)  # {'name': 'alex', 'age': 18}

del f1['name']  # 调用了__delitem__