class People(object):
    """注解：人类"""

    # 初始化函数
    def __init__(self, name):
        self.name = name

    # 析构函数，一般解释器会自动分配和释放内存，
    # 所以，析构函数的调用是由解释器在进行垃圾回收时自动触发执行的。
    def __del__(self):
        pass

    # print输出对象调用 print(people)
    def __str__(self):
        return "str函数被调用"

    # 直接使用对象时调用 people
    def __repr__(self):
        return "repr函数被调用"

    # 对象当做方法时调用，例people()
    def __call__(self, *args, **kwargs):
        print("call函数被调用")

    # 用于索引操作，可如字典般使用
    # 获取对象属性，people['name']
    def __getitem__(self, item):
        return getattr(self, item)

    # 设置对象属性，people['name'] = 'Jack'
    def __setitem__(self, key, value):
        setattr(self, key, value)

    # 删除对象属性，del people['name']
    def __delitem__(self, key):
        delattr(self, key)

    # 正常情况下，当我们调用类的方法或属性时，如果不存在，就会报错
    # 当对未定义的属性名称和实例进行点号运算时，就会用属性名作为字符串调用这个方法
    def __getattr__(self, item):
        if item == 'age':
            return 18

    # 会拦截所有属性的的赋值语句。如果定义了这个方法，self.arrt = value 就会变成self,__setattr__("attr", value)
    # 当在__setattr__方法内对属性进行赋值是，不可使用self.attr = value,因为他会再次调用self,__setattr__("attr", value),则会形成无穷递归循环，最后导致堆栈溢出异常
    # 应该通过对属性字典做索引运算来赋值任何实例属性，也就是使用self.__dict__['name'] = value
    def __setattr__(self, key, value):
        super().__setattr__(key, value)

    def __delattr__(self, key):
        super().__delattr__(key)


people = People('Jack')

print(people.__doc__)  # 注解：人类
print(People.__doc__)   # 注解：人类

print(people.__module__)    # __main__
print(People.__module__)    # __main__

print(people.__class__)  # <class '__main__.People'>
print(People.__class__)  # <class 'type'>

print(people.__dict__)  # {}
# {'__module__': '__main__', '__doc__': '注解：人类',
# '__init__': <function People.__init__ at 0x00000000037957B8>,
# '__del__': <function People.__del__ at 0x000000000D8A2A60>,
# '__str__': <function People.__str__ at 0x000000000D8A2AE8>,
# '__repr__': <function People.__repr__ at 0x000000000D8A2B70>,
# '__call__': <function People.__call__ at 0x000000000D8A2BF8>,
# '__getitem__': <function People.__getitem__ at 0x000000000D8A2C80>,
# '__setitem__': <function People.__setitem__ at 0x000000000D8A2D08>,
# '__delitem__': <function People.__delitem__ at 0x000000000D8A2D90>,
# '__getattr__': <function People.__getattr__ at 0x000000000D8A2E18>,
# '__setattr__': <function People.__setattr__ at 0x000000000D8A2EA0>,
# '__delattr__': <function People.__delattr__ at 0x000000000D8A2F28>,
# '__dict__': <attribute '__dict__' of 'People' objects>,
# '__weakref__': <attribute '__weakref__' of 'People' objects>}
print(People.__dict__)

print(People)  # <class '__main__.People'>
print(people)  # str函数被调用
people  # 啥也输出，不知道为啥
people()  # call函数被调用

print(people['name'])  # Jack
people['name'] = 'Tom'
print(people['name'])   # Tom
del people['name']
print(people['name'])   # None

print(people.age)   # 18