*7、類的賦值、淺拷貝、深拷貝
self.__age=age: self.__age前面有兩個"_",Describe this propertyCannot be accessed outside the class object
in the initialization method in the subclass super().__init__(name,age) It is to call the initialization method of the parent class to assign a value to the property,score 是 student own properties in the class,使用self進行賦值
class Person:
def __init__(self,name,age):
self.name=name
self.age=age
def info(self):
print(self.name,self.age)
#定義子類
class Student(Person):
def __init__(self,name,age,score):
super().__init__(name,age) #Call the initialization method of the parent class toname,age賦值
self.score=score #scoreis its own property in the class,故用self賦值
class Teacher(Person):
def __init__(self,name,age,teacheryear):
super().__init__(name,age) #Call the initialization method of the parent class toname,age賦值
self.teacheryear=teacheryear #teacheryearis its own property in the class,故用self賦值
stu=Student("張三",18,95)
teacher=Teacher("王梅",32,8)
stu.info()
teacher.info()python 中也可以實現 多繼承
class A(object):
pass
class B(object):
pass
class C(A,B): #C類同時繼承了A類,B類
pass
方法重寫：①Methods can be rewritten in subclasses
②Overridden methods are available in subclasses super().xx()Call the original method in the parent class (The same as the initialization method in the subclasssuper().__init__(name,age)statement calls the initialization method in the parent class)
③An arrow display appears when overriding a methodoverrides method in object
class Person: #父類
def __init__(self,name,age):
self.name=name
self.age=age
def info(self):
print(self.name,self.age)
#定義子類
class Student(Person):
def __init__(self,name,age,score):
super().__init__(name,age) #Call the initialization method of the parent class toname,age賦值
self.score=score #scoreis its own property in the class,故用self賦值
def info(self):
super().info() #Override in subclassesinfo方法,If you still want to use the method of the parent class to writesuper().info()
print(self.score) #A statement added after an overridden method
class Teacher(Person):
def __init__(self,name,age,teacheryear):
super().__init__(name,age) #Call the initialization method of the parent class toname,age賦值
self.teacheryear=teacheryear #teacheryearis its own property in the class,故用self賦值
stu=Student("張三",18,95)
teacher=Teacher("王梅",32,8)
stu.info()
teacher.info()
__str__（）I don't understand the method
After writing the class,通常對 __str__（）方法進行重寫
class Student: #Inherit if not specifiedobject類
pass
stu=Student()
print(dir(stu)) #內置函數dir()View all properties of the specified object
class Animal(object):
def eat(self):
print("動物會吃")
class Dog(Animal):
def eat(self):
print("狗吃骨頭")
class Cat(Animal):
def eat(self):
print("貓吃魚")
class Person(object):
def eat(self):
print("people eat anything")
def fun(obj):
obj.eat()
fun(Cat())
fun(Dog())
fun(Animal())
fun(Person()) #不用關心PersonWho's subclass of when,只關心Person是否具有eat方法
Don't care about the above code Person 是誰的子類,只關心Person是否具有eat方法
JAVA是靜態語言,Python是動態語言
以兩個下劃線"__"start and two underscores"__"End property or method,is a special property or method
類對象的__dict__屬性Include all of the classA dictionary of properties and methods,實例對象的__dict__屬性Include all of the instance object屬性的字典
print(x.__class__) #屬性__class__,輸出實例對象x所屬的類
print(C.__bases__) #屬性__bases__,輸出CMultiple parent classes that a class inherits and place the parent classes in a tuple
print(C.__mro__) #屬性__mro__,Output to view the class hierarchy,That is, the subclass parent class and the grandparent class
print(A.__subclasses__) #屬性__subclasses__,查看ASubclass the class and put the subclass in the list
If you want to add some properties of two instance objects,It needs to be overridden in the class__add__()方法(Understand the corresponding content in the table)
If you want to count the length of some properties of the instance object,It needs to be overridden in the class__len__()方法(Understand the corresponding content in the table)
①方框中的9360,7104是輸出的地址;箭頭表示傳參的過程
②由上圖可知先用__new__創建對象,再用__init__初始化對象
③上圖__new__方法中用了super().__new__(cls),使用父類objectThe method of creating an object in a class is passed as a parametercls
淺拷貝：Subobject refers to Instance objects of other classes included in this source object,The source object and the copy object refer to the same one
子對象
深拷貝：The child objects contained in the object are copied,All child objects of the source object and the copy object are not the same
