今日内容:
1、多继承的正确打开方式:mixins机制
2、在子类派生的新方法中如何重用父类的功能
方式一:指名道姓调用某一个类下的函数=》不依赖于继承关系
方式二:super()调用父类提供给自己的方法=》严格依赖继承关系
3、多态与鸭子类型
4、绑定方法与非绑定方法
classmethod
staticmethod
5、内置函数
mixins机制
# 多继承的正确打开方式:mixins机制
# mixins机制核心:就是在多继承背景下尽可能地提升多继承的可读性
# ps:让多继承满足人的思维习惯=》什么"是"什么
class Vehicle:
pass
class FlyableMixin:
def fly(self):
pass
class CivilAircraft(FlyableMixin,Vehicle): # 民航飞机
pass
class Helicopter(FlyableMixin,Vehicle): # 直升飞机
pass
class Car(Vehicle): # 汽车并不会飞,但按照上述继承关系,汽车也能飞了
pass
import socketserver
# 补充:通常Mixin结果的类放在左边
02 在子类派生的新方法中如何重用父类的功能
# 在子类派生的新方法中如何重用父类的功能
# 方式一:指名道姓调用某一个类下的函数=》不依赖于继承关系
# class OldboyPeople:
# def __init__(self,name,age,sex):
# self.name=name
# self.age=age
# self.sex=sex
#
# def f1(self):
# print('%s say hello' %self.name)
#
#
# class Teacher(OldboyPeople):
# def __init__(self,name,age,sex,level,salary):
# OldboyPeople.__init__(self,name,age,sex)
#
# self.level = level
# self.salary=salary
#
# tea_obj=Teacher('egon',18,'male',10,3000)
# print(tea_obj.__dict__)
# 方式二:super()调用父类提供给自己的方法=》严格依赖继承关系
# 调用super()会得到一个特殊的对象,该对象会参照发起属性查找的那个类的mro,去当前类的父类中找属性
# class OldboyPeople:
# def __init__(self,name,age,sex):
# self.name=name
# self.age=age
# self.sex=sex
#
# def f1(self):
# print('%s say hello' %self.name)
#
#
# class Teacher(OldboyPeople):
# def __init__(self,name,age,sex,level,salary):
# # super(Teacher,self).__init__(name,age,sex)
# super().__init__(name,age,sex) # 调用的是方法,自动传入对象
#
# self.level = level
# self.salary=salary
#
# # print(Teacher.mro())
# tea_obj=Teacher('egon',18,'male',10,3000)
# print(tea_obj.__dict__)
# super()案例
# class A:
# def test(self):
# print('from A')
# super().test()
#
# class B:
# def test(self):
# print('from B')
#
# class C(A,B):
# pass
#
#
# obj=C()
# obj.test()
#
# print(C.mro())
class A:
def test(self):
print('from A')
super().test1()
class B:
def test(self):
print('from B')
class C(A,B):
def test1(self):
print('from C')
obj=C()
obj.test()
print(C.mro())
3、多态与鸭子类型
# 1、什么多态:同一事物有多种形态
# class Animal:
# pass
#
# class People(Animal):
# pass
#
# class Dog(Animal):
# pass
#
# class Pig(Animal):
# pass
# 2、为何要有多态=》多态会带来什么样的特性,多态性
# 多态性指的是可以在不考虑对象具体类型的情况下而直接使用对象
# class Animal: # 统一所有子类的方法
# def say(self):
# print('动物基本的发声频率。。。',end=' ')
#
# class People(Animal):
# def say(self):
# super().say()
# print('嘤嘤嘤嘤嘤嘤嘤')
#
# class Dog(Animal):
# def say(self):
# super().say()
# print('汪汪汪')
#
# class Pig(Animal):
# def say(self):
# super().say()
# print('哼哼哼')
#
#
# obj1=People()
# obj2=Dog()
# obj3=Pig()
#
# obj1.say()
# obj2.say()
# obj3.say()
# 定义统一的接口,接收传入的动物对象
# def animal_say(animal):
# animal.say()
#
# animal_say(obj1)
# animal_say(obj2)
# animal_say(obj3)
# print('hello'.__len__())
# print([1,2,3].__len__())
# print({'a':1,'b':2}.__len__())
#
# def my_len(val):
# return val.__len__()
# print(my_len('hello'))
# print(my_len([1,2,3]))
# print(my_len({'a':1,'b':2}))
# len('hello')
# len([1,2,3])
# len({'a':1,'b':2})
# python推崇的是鸭子类型
# class Cpu:
# def read(self):
# print('cpu read')
#
# def write(self):
# print('cpu write')
#
# class Mem:
# def read(self):
# print('mem read')
#
# def write(self):
# print('mem write')
#
#
# class Txt:
# def read(self):
# print('txt read')
#
# def write(self):
# print('txt write')
#
#
# obj1=Cpu()
# obj2=Mem()
# obj3=Txt()
#
# obj1.read()
# obj1.write()
#
# obj2.read()
# obj2.write()
#
# obj3.read()
# obj3.write()
# 了解:
import abc
class Animal(metaclass=abc.ABCMeta): # 统一所有子类的标准
@abc.abstractmethod
def say(self):
pass
# obj=Animal() # 不能实例化抽象类自己
class People(Animal):
def say(self):
pass
class Dog(Animal):
def say(self):
pass
class Pig(Animal):
def say(self):
pass
#
# obj1=People()
# obj2=Dog()
# obj3=Pig()
4、绑定方法与非绑定方法
classmethod
staticmethod
# 一:绑定方法:特殊之处在于将调用者本身当做第一个参数自动传入
# 1、绑定给对象的方法:调用者是对象,自动传入的是对象
# 2、绑定给类的方法:调用者类,自动传入的是类
# import settings
#
# class Mysql:
# def __init__(self,ip,port):
# self.ip=ip
# self.port=port
#
# def func(self):
# print('%s:%s' %(self.ip,self.port))
#
# @classmethod # 将下面的函数装饰成绑定给类的方法
# def from_conf(cls):
# print(cls)
# return cls(settings.IP, settings.PORT)
#
# # obj1=Mysql('1.1.1.1',3306)
#
# obj2=Mysql.from_conf()
# print(obj2.__dict__)
# 二:非绑定方法-》静态方法:
# 没有绑定给任何人:调用者可以是类、对象,没有自动传参的效果
class Mysql:
def __init__(self,ip,port):
self.nid=self.create_id()
self.ip=ip
self.port=port
@staticmethod # 将下述函数装饰成一个静态方法
def create_id():
import uuid
return uuid.uuid4()
@classmethod
def f1(cls):
pass
def f2(self):
pass
obj1=Mysql('1.1.1.1',3306)
# print(Mysql.create_id)
# print(obj1.create_id)
# Mysql.create_id(1,2,3)
# obj1.create_id(4,5,6)
print(Mysql.create_id)
print(Mysql.f1)
print(obj1.f2)
5、内置函数
# print(abs(-1))
# print(all([1,'aaa','1']))
# print(all([]))
# print(any([0,None,1]))
# print(any([]))
# print(bin(11))
# print(oct(11))
# print(hex(11))
# print(bool(''))
# def func():
# pass
# class Foo:
# pass
# print(callable(Foo)) # 方
# print(chr(65))
# print(ord('A'))
# 不可变集合
# s=frozenset({1,2,3})
# hash(不可变类型)
# print(round(1.5))
# print(round(1.4))
# 10 ** 2 % 3
# print(pow(10,2,3))
# s=slice(1,4,2)
# l1=['a','b','c','d','e']
# l2=['aaa','bbb','ccc','ddd',444]
#
# print(l1[1:4:2]) # l1[s]
# print(l2[1:4:2]) # l2[s]
# =================》掌握
# v1='hello'
# v2=[111,222,333,444,5555,6666]
# res=zip(v1,v2)
# print(list(res))
# =================》掌握
# print(divmod(10000,33))
# =================》掌握
# class Foo:
# pass
# obj=Foo()
# obj.xxx=1111
# print(dir(obj)) # obj.哪些属性
# =================》掌握
# for i,v in enumerate(['a','b','c']):
# print(i,v)
# =================》掌握
# res=eval('{"a":1}') # 执行字符串中的表达式
# print(res,type(res))
# =================》掌握
# class Foo:
# pass
# obj=Foo()
# print(isinstance(obj,Foo))
# print(isinstance([],list)) # 类型判断推荐使用isinstance
# print(type([]) is list) # 不推荐使用
# =================》掌握
# import 'time' # 错误
time=__import__('time')
time.sleep(3)
# 下个周:反射
# setattr
# getattr
# delattr
# hasattr