路飞学城Python-Day20(元类的练习题)

class MyDef(type):
def __new__(cls, class_name, class_attr, class_dic):
upper_data = {}
for k,v in class_dic.items():
if not callable(v) and not k.startswith('__'):
upper_data[k.upper()] = v
else:
upper_data[k] = v
return type.__new__(cls, class_name, class_attr, upper_data)

class People(metaclass=MyDef):
time = 'now'
work = 'weekends'

print(People.__dict__)

class MyDef(type):
def __call__(self, *args, **kwargs):
if args:
raise TypeError(' must use keyword argument')
obj = object.__new__(self)
for k,v in kwargs.items():
obj.__dict__[k.upper()] = v
return obj

class People(metaclass=MyDef):
tag = 'China'
some = 'None'

p1 = People(name = 'panda')
print(p1.__dict__)

# 在元类中控制自定义的类产生的对象相关的属性全部为隐藏属性
class Mymeta(type):
def __init__(self, class_name, class_bases, attr):
super(Mymeta, self).__init__(class_name, class_bases, attr)

def __call__(self, *args, **kwargs):
obj = self.__new__(self)
self.__init__(obj, *args, **kwargs )
obj.__dict__ = {'_%s__%s' % (self.__name__, k): v for k, v in obj.__dict__.items()}
return obj
class P(metaclass=Mymeta):
def __init__(self, name, age):
self.name = name
self.age = age
p1 = P('123','567')
print(p1._P__name)