class Role(object):     ac = None;     count = 0     def __init__(self,name, role, weapon, life_value):         self.name = name;         self.role = role;         self.weapon = weapon;         self.life_value = life_value;         Role.count += 1     def buy_weapon(self,weapon):         print ("%s is buying [%s]" %(self.name, weapon))         self.weapon = weapon p1 = Role("zhangsan", 'Police', "B10", 100) t1 = Role("lisi", 'Terrorist', "B11", 90) p1.buy_weapon("AK47") t1.buy_weapon("B51") print("p1:" , p1.weapon) print("t1:" , t1.weapon) p1.ac = "China" t1.ac = "USA" print(p1.ac) print(t1.ac) p1.count = 3;           在p1 中创建一个 count 变量 print(Role.count)       类中的count 变量 print(p1.count) print(t1.count)         实例中如果没有创建同名的类变量，则访问的是 类变量。

　　输出：

zhangsan is buying [AK47]

lisi is buying [B51]

p1: AK47

t1: B51

China

USA

2

3

2

class Role(object):   括号中的是继承的父类。

def __init__(self,name, role, weapon, life_value): 是构造方法。

p1 = Role("zhangsan", 'Police', "B10", 100) 实例化。 相当于 Role(p1,"zhangsan", 'Police', "B10", 100 )

p1.buy_weapon("AK47")   相当于 Role.buy_weapon(p1,"AK47")     self 代表实例本身。