按照Python100days项目中的该方法来访问私有属性，可正常访问到：
class Test:
def __init__(self, foo):
self.__foo = foo
def __bar(self):
print(self.__foo)
print('__bar')
def main():
test = Test('hello')
test._Test__bar()
print(test._Test__foo)
if __name__ == "__main__":
main()
但是，当下面的项目中使用objectname._classname__attributionname的方式就访问不到对象u = Ultraman('骆昊', 1000, 120)的私有属性__name了。代码中使用了print('name: ', u._Ultraman__name)，出现AttributeError: _Ultraman__name。
"""
"""
@author: Zhangsan
@date: 2023/4/3 17:31
@file: day08_eg1.py
@Software: Pycharm
"""
# !/usr/bin/env python3
# coding=utf-8
from abc import ABCMeta, abstractmethod
from random import randint, randrange
class Fighter(object, metaclass=ABCMeta):
__slots__ = ('_name', '_hp')
def __init__(self, name, hp):
self._name = name
self._hp = hp
@property
def name(self):
return self._name
@property
def hp(self):
return self._hp
@hp.setter
def hp(self, hp):
self._hp = hp if hp >= 0 else 0
@property
def alive(self):
return self._hp > 0
@abstractmethod
def attack(self, other):
pass
class Ultraman(Fighter):
__slots__ = ('_name', '_hp', '_mp')
def __init__(self, name, hp, mp):
"""
:param name:
:param hp: 生命值
:param mp: 魔法值
"""
super().__init__(name, hp)
self._mp = mp
def attack(self, other):
other.hp -= randint(15, 25) #zh:为什么是“other.hp”，而不是“other._hp” # 是不是因为在对象的外部访问不到私有属性，使用使用getter和setter方法
print('other._hp: ', other._hp)
def huge_attack(self, other):
"""若自身魔法值充足（大于50），则至少打掉对方50点或四分之三的血量
:param other: 被攻击的对象
:return: 使用成功，返回True；否则，返回False
"""
if self._mp >= 50:
self._mp -= 50
injury = other.hp * 3 // 4
injury = injury if injury >= 50 else 50
other.hp -= injury
return True
else:
self.attack(other)
return False
def magic_attack(self, others):
if self._mp >= 20:
self._mp -= 20
for temp in others:
if temp.alive:
temp.hp -= randint(10, 15)
return True
else:
return False
def resume(self):
incr_point = randint(1, 10)
self._mp += incr_point
return incr_point
def __str__(self):
return f'~~~{self._name}奥特曼~~~\n生命值：{self._hp}\n' \
f'生命值：{self._hp}\n魔法值：{self._mp}\n'
class Monster(Fighter):
__slots__ = ('_name', '_hp')
def attack(self, other):
other.hp -= randint(10, 20)
def __str__(self):
return f'~~~{self._name}~~~\n生命值：{self._hp}\n'
def is_ang_alive(monsters):
"""判断有没有小怪兽是活着的"""
for monster in monsters:
if monster.alive > 0:
return True
return False
def select_alive_one(monsters):
"""选择一只活着的小怪兽"""
monsters_len = len(monsters)
while True:
index = randrange(monsters_len)
monster = monsters[index]
if monster.alive > 0:
return monster
def display_info(ultraman, monsters):
"""显示奥特曼和小怪兽的信息"""
print(ultraman)
for monster in monsters:
print(monster)
def main():
u = Ultraman('骆昊', 1000, 120)
print('name: ', u._Ultraman__name)
m1 = Monster('狄仁杰', 250)
m2 = Monster('白远方', 500)
m3 = Monster('王大锤', 750)
ms = [m1, m2, m3]
fight_round = 1
while u.alive and is_ang_alive(ms):
print('===========第%02d回合===========' % fight_round)
m = select_alive_one(ms) # 选中一只小怪兽
skill = randint(1, 10) # 通过随机数来随机选取使用的技能
if skill <= 6: # 60%的概率使用普通攻击
print('%s使用普通攻击打了%s.' % (u.name, m.name))
u.attack(m)
print('%s的魔法值恢复了%d点' % (u.name, u.resume()))
elif skill <= 9: # 30%的概率使用魔法攻击
if u.magic_attack(ms):
print('%s使用了魔法攻击.' % u.name)
else:
print('%s使用魔法攻击失败.' % u.name)
else: # 10%的概率使用究极必杀技
if u.huge_attack(m):
print(f'{u.name}使用了究极必杀技虐杀了{m.name}')
else:
print('%s使用了普通攻击打了%s' % (u.name, m.name))
print('%s的魔法值恢复了%d点' % (u.name, u.resume()))
if m.alive > 0:
print('%s回击了%s' %(m.name, u.name))
m.attack(u)
display_info(u, ms) # 每个回合结束显示奥特曼和小怪兽的信息
fight_round += 1
if u.alive > 0:
print(f'{u.name}奥特曼胜利了')
else:
print('小怪兽胜利了')
if __name__ == '__main__':
main()
目前尚未找到原因，先记录下(2023.04.04)
由于上述代码中使用到了一个抽象类Figher和它对应的两个继承类Ultraman和Monster，因而在类的内部或外部中使用_classname_attribute来调用类的私有属性时，会出现AttributeError。其主要原因是：继承类中的私有属性是源自抽象类的私有属性，当在继承类中使用基类的私有属性时需要使用_baseclassname_attribute来调用类的私有属性，而不是_inheritingclassname_attribute来调用类的私有属性。
下面先分析基类Fighter（抽象类）和它的两个继承类Ultraman和Monster的具体情况。
Fighter: __slots__ = ('__name', '__hp')
# 故假设存在私有属性： _Fighter__name 和 _Fighter__hp
Ultraman: __slots__ = ('__name', '__hp', '__mp')
# 重点：故在Ultraman类中实际存在的私有属性是： _Fighter__name 、 _Fighter__hp、 _Ultraman__mp （而不是_Ultraman__name）
Fighter: __slots__ = ('__name', '__hp')
# 故存在私有属性： _Fighter__name 和 _Fighter__hp
上述过程可通过debug发现如下结构：
发现在Ultraman类中_Ultraman__name为TracebackError。
修改后的正确代码如下：（**此处代码和上述代码中命名私有属性的方式不同：**上面将_name视为私有属性，下面代码中将__name视为私有属性）
from abc import ABCMeta, abstractmethod
from random import randint, randrange
class Fighter(object, metaclass=ABCMeta):
__slots__ = ('__name', '__hp')
def __init__(self, name, hp):
self.__name = name
self.__hp = hp
@property
def name(self):
return self.__name
@property
def hp(self):
return self.__hp
@hp.setter
def hp(self, hp):
self.__hp = hp if hp >= 0 else 0
@property
def alive(self):
return self.__hp > 0
@abstractmethod
def attack(self, other):
pass
class Ultraman(Fighter):
__slots__ = ('__name', '__hp', '__mp')
def __init__(self, name, hp, mp):
"""
:param name:
:param hp: 生命值
:param mp: 魔法值
"""
super().__init__(name, hp)
self.__mp = mp
def attack(self, other):
other.hp -= randint(15, 25) #zh:为什么是“other.hp”，而不是“other._hp” # 是不是因为在对象的外部访问不到私有属性，使用使用getter和setter方法
# print('other.__hp: ', other.__hp)
print('other.__hp: ', other.hp)
def huge_attack(self, other):
"""若自身魔法值充足（大于50），则至少打掉对方50点或四分之三的血量
:param other: 被攻击的对象
:return: 使用成功，返回True；否则，返回False
"""
if self.__mp >= 50:
self.__mp -= 50
injury = other.hp * 3 // 4
injury = injury if injury >= 50 else 50
other.hp -= injury
return True
else:
self.attack(other)
return False
def magic_attack(self, others):
if self.__mp >= 20:
self.__mp -= 20
for temp in others:
if temp.alive:
temp.hp -= randint(10, 15)
return True
else:
return False
def resume(self):
incr_point = randint(1, 10)
self.__mp += incr_point
return incr_point
def __str__(self):
return f'~~~{self._Fighter__name}奥特曼~~~\n生命值：{self._Fighter__hp}\n' \
f'魔法值：{self._Ultraman__mp}\n'
class Monster(Fighter):
__slots__ = ('__name', '__hp')
def attack(self, other):
other.hp -= randint(10, 20)
def __str__(self):
return f'~~~{self._Fighter__name}~~~\n生命值：{self._Fighter__hp}\n'
def is_ang_alive(monsters):
"""判断有没有小怪兽是活着的"""
for monster in monsters:
if monster.alive > 0:
return True
return False
def select_alive_one(monsters):
"""选择一只活着的小怪兽"""
monsters_len = len(monsters)
while True:
index = randrange(monsters_len)
monster = monsters[index]
if monster.alive > 0:
return monster
def display_info(ultraman, monsters):
"""显示奥特曼和小怪兽的信息"""
print(ultraman)
for monster in monsters:
print(monster)
def main():
u = Ultraman('骆昊', 1000, 120)
# print('name: ', u._Ultraman__name) # zh:AttributeError: _Ultraman__name
print('name: ', u._Fighter__name)
m1 = Monster('狄仁杰', 250)
m2 = Monster('白远方', 500)
m3 = Monster('王大锤', 750)
ms = [m1, m2, m3]
fight_round = 1
while u.alive and is_ang_alive(ms):
print('===========第%02d回合===========' % fight_round)
m = select_alive_one(ms) # 选中一只小怪兽
skill = randint(1, 10) # 通过随机数来随机选取使用的技能
if skill <= 6: # 60%的概率使用普通攻击
print('%s使用普通攻击打了%s.' % (u.name, m.name))
u.attack(m)
print('%s的魔法值恢复了%d点' % (u.name, u.resume()))
elif skill <= 9: # 30%的概率使用魔法攻击
if u.magic_attack(ms):
print('%s使用了魔法攻击.' % u.name)
else:
print('%s使用魔法攻击失败.' % u.name)
else: # 10%的概率使用究极必杀技
if u.huge_attack(m):
print(f'{u.name}使用了究极必杀技虐杀了{m.name}')
else:
print('%s使用了普通攻击打了%s' % (u.name, m.name))
print('%s的魔法值恢复了%d点' % (u.name, u.resume()))
if m.alive > 0:
print('%s回击了%s' %(m.name, u.name))
m.attack(u)
display_info(u, ms) # 每个回合结束显示奥特曼和小怪兽的信息
fight_round += 1
if u.alive > 0:
print(f'{u.name}奥特曼胜利了')
else:
print('小怪兽胜利了')
if __name__ == '__main__':
main()