Python OOP-5

    import abc

# 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 MethodType
class 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'