# 变量的三种用法
class A():    def __init__(self):        self.name = "haha"        self.age = 18        a = A()# 属性的三种用法# 1. 赋值# 2. 读取# 3. 删除a.name = "ruochen"print(a.name)del a.name# print(a.name)

ruochen

# 类属性 property# 应用场景：# 对变量除了普通的三种操作，还想增加一些附加的操作，那么可以通过property完成class A():    def __init__(self):        self.name = "haha"        self.age = 18    # 此功能，是对类变量读取操作的时候应该执行的函数功能    def fget(self):        print("我被读取了")        return self.name    # 模拟的是对变量进行写操作的时候执行的功能    def fset(self, name):        print("我被写入了，但是还可以做好多事情")        self.name = name + "1"     # fdel模拟的是删除变量的时候进行的操作       def fdel(self):        pass        # property的四个参数顺序的固定的    # 第一个参数代表读取的时候需要调用的函数    # 第二个参数代表写入的时候需要调用的函数    # 第三个是删除    name2 = property(fget, fset, fdel, "这是一个property的例子")    a = A()print(a.name)
print(a.name2)

haha我被读取了haha

# 抽象
class Animel():        def sayHello(self):        pass    class Dog(Animel):        def sayHello(self):        print("问一下对方")
class Person(Animel):        def sayHello(self):        print("Kiss me")        d = Dog()d.sayHello()
p = Person()p.sayHello()

问一下对方Kiss me

# 抽象类的实现
import abc
# 声明一个类并且指定当前类的元类class Hunam(metaclass=abc.ABCMeta):        # 定义一个抽象的方法    @abc.abstractmethod    def smoking(self):        pass        # 定义类抽象方法    @abc.abstractclassmethod    def drink():        pass        # 定义静态抽象方法    @abc.abstractstaticmethod    def play():        pass        def sleep(self):        print("Sleeping......")

# 函数名可以当变量使用
def sayHello(name):    print("{}你好".format(name))
sayHello("A")
liumang = sayHello
liumang("A")

A你好A你好

# 自己组装一个类
class A():    pass
def say(self):    print("Saying... ...")    class B():    def say(self):        print("Saying... ...")        say(9)
A.say = say
a = A()a.say()
b = B()b.say()

Saying... ...Saying... ...Saying... ...

# 组装类例子 2# 自己组装一个类from types import MethodTypeclass A():    pass
def say(self):    print("Saying... ...")    a = A()a.say = MethodType(say, A)a.say()

Saying... ...

help(MethodType)

Help on class method in module builtins:
class method(object) |  method(function, instance) |   |  Create a bound instance method object. |   |  Methods defined here: |   |  __call__(self, /, *args, **kwargs) |      Call self as a function. |   |  __delattr__(self, name, /) |      Implement delattr(self, name). |   |  __eq__(self, value, /) |      Return self==value. |   |  __ge__(self, value, /) |      Return self>=value. |   |  __get__(self, instance, owner, /) |      Return an attribute of instance, which is of type owner. |   |  __getattribute__(self, name, /) |      Return getattr(self, name). |   |  __gt__(self, value, /) |      Return self>value. |   |  __hash__(self, /) |      Return hash(self). |   |  __le__(self, value, /) |      Return self<=value. |   |  __lt__(self, value, /) |      Return self<value. |   |  __ne__(self, value, /) |      Return self!=value. |   |  __reduce__(...) |      Helper for pickle. |   |  __repr__(self, /) |      Return repr(self). |   |  __setattr__(self, name, value, /) |      Implement setattr(self, name, value). |   |  ---------------------------------------------------------------------- |  Static methods defined here: |   |  __new__(*args, **kwargs) from builtins.type |      Create and return a new object.  See help(type) for accurate signature. |   |  ---------------------------------------------------------------------- |  Data descriptors defined here: |   |  __func__ |      the function (or other callable) implementing a method |   |  __self__ |      the instance to which a method is bound

type(8)

int

# 利用type造一个类
# 先定义类应该具有的成员函数def say(self):    print("Saying... ...")    def talk(self):    print("Talking... ...")    # 利用type来创建一个类A = type("AName", (object, ), {"class_say":say, "class_talk":talk})
# 然后可以像正常一样使用类a = A()dir(a)a.class_say()

Saying... ...

# 元类演示
# 元类写法是固定的，他必须继承于type# 元类一般命名以MetaClass结尾class CMetaClass(type):    # 注意以下写法    def __new__(cls, name, bases, attrs):        # 自己的业务处理        print("我是元类")        attrs['id'] = '000000'        attrs['addr'] = "1"        return type.__new__(cls, name, bases, attrs)    # 元类定义完就可以使用，使用注意写法class Teacher(object, metaclass=CMetaClass):    pass
t = Teacher()
t.__dict__t.id

我是元类




'000000'