实例属性的增删改查

class Chinese:
    def __init__(self, name):
        self.name = name

    def play_ball(self):
        print('%s 正在打篮球' % self.name)


p1 = Chinese('小白')
p1.age = 19    # 实例只有数据属性，没有函数属性
print(p1.__dict__)
del p1.age
print(p1.__dict__)
输出：
{'name': '小白', 'age': 19}
{'name': '小白'}

 1 class MyData:
 2     pass
 3 x = 1
 4 y = 2
 5 MyData.x = 1
 6 MyData.y = 2
 7 p1 = MyData()
 8 print(p1.x)
 9 输出：
10 1

 1 class Chinese:
 2     country = 'china'
 3     def __init__(self, name):
 4         self.name = name
 5 
 6     def play_ball(self):
 7         print('%s 正在打篮球' % self.name)
 8 
 9 
10 p1 = Chinese('alex')
11 p1.country = 'japan'
12 print(p1.country)
13 print(Chinese.country)
14 输出：
15 japan
16 china