python面向对象

class Goods(object):
    def __init__(self):
        # 原价
        self.original_price = 100
        # 折扣
        self.discount = 0.8
    @property
    def price(self):
        new_price = self.original_price * self.discount
        return new_price
    @price.setter
    def price(self, value):
        self.original_price = value
    @price.deleter
    def price(self):
        del self.original_price

obj = Goods()
print(obj.price)
obj.price = 200
print(obj.price)
del obj.price

class C:
    __name = "私有静态字段"
    def func(self):
        print(C.__name)    # 类内部可以访问
class D(C):
    def show(self):
        print(C.__name)    # 派生类中不可以访问

print(C.__name)            # 类不可以访问
obj = C()

obj.func()
obj_son = D()
obj_son.show()

如果想要强制访问私有字段，可以通过 【对象._类名__私有字段明 】访问（如：obj._C__foo），不建议强制访问私有成员。

class C:
    def __init__(self):
        self.__foo = "私有字段"
    def func(self):
        print self.foo 　#　类内部访问
class D(C):
    def show(self):
        print self.foo　＃　派生类中访问
obj = C()
obj.__foo     # 通过对象访问    ==> 错误
obj.func()  # 类内部访问        ==> 正确
obj_son = D();
obj_son.show()  # 派生类中访问  ==> 错误