python:属性查找与绑定方法

# 类的数据属性是所有对象共享的，id是一样的
print(id(OldboyStudent.school))     # 4830576
print(id(s1.school))        # 4830576
print(id(s2.school))        # 4830576
print(id(s3.school))        # 4830576

# 类的函数属性是绑定给对象使用的,obj.method称为绑定方法,内存地址都不一样
print(OldboyStudent.learn)      # <function OldboyStudent.learn at 0x0000000002879598>
print(s1.learn)                 # <bound method OldboyStudent.learn of <__main__.OldboyStudent object at 0x0000000002866898>>
print(s2.learn)                 # <bound method OldboyStudent.learn of <__main__.OldboyStudent object at 0x00000000028669E8>>
print(s3.learn)                 # <bound method OldboyStudent.learn of <__main__.OldboyStudent object at 0x0000000002866F98>>

#ps:id是python的实现机制,并不能真实反映内存地址,如果有内存地址,还是以内存地址为准

class OldboyStudent:
    school = ‘oldboy‘
    def __init__(self, name, age, sex):
        self.name = name
        self.age = age
        self.sex = sex

    def learn(self):
        print(‘%s is learning‘ % self.name)     # 新增self.name

    def eat(self):
        print(‘%s is eating‘ % self.name)

    def sleep(self):
        print(‘%s is sleeping‘ % self.name)


s1 = OldboyStudent(‘李坦克‘, ‘男‘, 18)
s2 = OldboyStudent(‘王大炮‘, ‘男‘, 28)
s3 = OldboyStudent(‘牛弹琴‘, ‘女‘, 38)

OldboyStudent.learn(s1)         # 李坦克 is learning
OldboyStudent.eat(s2)            # 王大炮 is eating
OldboyStudent.sleep(s3)        # 牛弹琴 is sleeping　　

s1.learn()  # 等同于OldboyStudent.learn(s1)
s2.eat()    # 等同于OldboyStudent.eat(s2)
s3.sleep()  # 等同于OldboyStudent.sleep(s3)

#类型dict就是类dict
>>> list
<class ‘list‘>

#实例化的到3个对象l1,l2,l3
>>> l1=list()
>>> l2=list()
>>> l3=list()

#三个对象都有绑定方法append,是相同的功能,但内存地址不同
>>> l1.append
<built-in method append of list object at 0x10b482b48>
>>> l2.append
<built-in method append of list object at 0x10b482b88>
>>> l3.append
<built-in method append of list object at 0x10b482bc8>

#操作绑定方法l1.append(3),就是在往l1添加3,绝对不会将3添加到l2或l3
>>> l1.append(3)
>>> l1
[3]
>>> l2
[]
>>> l3
[]
#调用类list.append(l3,111)等同于l3.append(111)
>>> list.append(l3,111) #l3.append(111)
>>> l3
[111]

# 练习1：编写一个学生类，产生一堆学生对象， (5分钟)
#
# 要求：
#
# 有一个计数器（属性），统计总共实例了多少个对象

class Student():
    school = "家里蹲大学"
    count = 0

    def __init__(self, name, age, sex):
        self.name = name
        self.age = age
        self.sex = sex
        Student.count += 1

    def learn(self):
        print(‘%s is learning‘ % self.name)

s1 = Student(‘张三‘, ‘男‘, 22)
s1.learn()
s2 = Student(‘李四‘, ‘女‘, 28)
print(Student.count)
print(s1.count)

# 练习2：模仿三国定义两个英雄类， (10分钟)
#
# 要求：
#
# 英雄需要有昵称、攻击力、生命值等属性；
# 实例化出两个英雄对象；
# 英雄之间可以互殴，被殴打的一方掉血，血量小于0则判定为死亡。
class Garen:
    camp = ‘Demacia‘

    def __init__(self, nickname, life_value, aggresivity):
        self.nickname = nickname
        self.life_value = life_value
        self.aggresivity = aggresivity

    def attack(self, enemy):
        enemy.life_value -= self.aggresivity
        if enemy.life_value <= 0:
            print(‘%s已经死亡‘ % self.nickname)

class Riven:
    camp = ‘Noxus‘

    def __init__(self, nickname, life_value, aggresivity):
        self.nickname = nickname
        self.life_value = life_value
        self.aggresivity = aggresivity

    def attack(self, enemy):
        enemy.life_value -= self.aggresivity
        if enemy.life_value <= 0:
            print(‘%s已经死亡‘ % self.nickname)


g1 = Garen(‘曹操‘, 100, 30)
r1 = Riven(‘刘备‘, 100, 50)

print(r1.life_value)
g1.attack(r1)
g1.attack(r1)
g1.attack(r1)
g1.attack(r1)
print(r1.life_value)