几段 Python 代码理解面向对象

正文

1.定义一个游戏输入，对输入简单解析并做出反应

源代码：

a-simple-game.py

# 获取输入并解析出输入对应的动作
def get_input():
    command = input(\":\").split()
    verbo_word = command[0]
    if verbo_word in verb_dict:
        verb = verb_dict[verbo_word]
    else:
        print(\"Unknown verb {}\".format(verbo_word))
        return

    if len(command) >= 2:
        noun_word = command[1]
        print(verb(noun_word))
    else:
        print(verb(\"nothing\"))

# 具体的动作
def say(noun):
    return \"You said {}\".format(noun)

# 将动词和动作对应起来
verb_dict = {
    \"say\": say,
}

while True:
    get_input()

运行结果：

2.为游戏对象添加查看状态的方法

代码：

class GameObject:
    class_name = \"\"
    desc = \"\"
    objects = {}

    def __init__(self, name):
        self.name = name
        GameObject.objects[self.class_name] = self

    def get_desc(self):
        return self.class_name + \"\\n\" + self.desc


# 创建一个继承自游戏对象类的哥布林类
class Goblin(GameObject):
    class_name = \"goblin\"
    desc = \"A foul creature\"

goblin = Goblin(\"Gobbly\")

# 具体的动作
def examine(noun):
    if noun in GameObject.objects:
        return GameObject.objects[noun].get_desc()
    else:
        return \"There is no {} here.\".format(noun)

以上代码创建了一个继承自 GameObject 类的 Goblin 类，也创建一个新的 examine 方法，于是我们添加一个新的 examine 动词进去：

# 将动词和动作对应起来
verb_dict = {
    \"say\": say,
    \"examine\": examine,
}

代码和上一个小 demo 合并起来，运行看看：

3.为 Goblin 类添加更详细的信息，并添加 hit 动作，让你可以打 Goblin（有点意思了~）

代码（只列出修改过的与添加的）：

class Goblin(GameObject):
    def __init__(self, name):
        self.class_name = \"goblin\"
        self.health = 3
        self._desc = \"A foul creature\"
        super().__init__(name)

    @property
    def desc(self):
        if self.health >= 3:
            return self._desc
        elif self.health == 2:
            health_line = \"It has a wound on its knee.\"
        elif self.health == 1:
            health_line = \"Its left arm has been cut off.\"
        elif self.health <= 0:
            health_line = \"It is dead.\"
        return self._desc + \"\\n\" + health_line

    @desc.setter
    def desc(self, value):
        self._desc = value

def hit(noun):
    if noun in GameObject.objects:
        thing = GameObject.objects[noun]
        if type(thing) == Goblin:
            thing.health -= 1
            if thing.health <= 0:
                msg = \"You killed the goblin!\"
            else:
                msg = \"You hit the {}\".format(thing.class_name)
        else:
            msg = \"I\'m not strong enough, I can only hit goblin.\"
    else:
        msg = \"There is no {} here.\".format(noun)
    return msg

# 将动词和动作对应起来
verb_dict = {
    \"say\": say,
    \"examine\": examine,
    \"hit\": hit,
}

运行：