class Foo(object):
    def __init__(self):
        self.data = {}
    def __getitem__(self, key):
        print(‘__getitem__‘, key)
        return self.data.get(key)
    def __setitem__(self, key, value):
        print(‘__setitem__‘, key, value)
        self.data[key] =value
    def __delitem__(self, key):
        print(‘__delitem__‘, key)


obj = Foo()
obj[‘name‘] = "alex"
# print(obj[‘name‘])
# print(obj.data)
del obj["sdfdsf"]
# result = obj[‘k1‘]  # 自動觸發執行 __getitem__
# obj[‘k2‘] = ‘alex‘  # 自動觸發執行 __setitem__
# del obj[‘k1‘]

__setitem__ name alex
__delitem__ sdfdsf

__getitem__\__setitem__\__delitem__