Three main features of Python object-oriented: encapsulation, inheritance, and polymorphism (example)

Inherited

Single Inheritance:

#类定义class people:    #定义基本属性    name = ' Age    = 0    #定义私有属性, private properties cannot be accessed directly outside the class    __weight = 0    #定义构造方法    def __init__ (self,n,a,w):        self.name = n        self.age = a        self.__weight = w    def speak (self):        Print ("%s" says: I'm%d years old.) "% (self.name,self.age)) #单继承示例class Student (people):    grade ="    def __init__ (self,n,a,w,g):        #调用父类的构函        people.__init__ (self,n,a,w)        self.grade = g    #覆写父类的方法    def speak (self):        print ("%s" said: I'm%d years old, I'm reading grade%d "% (Self.name,self.age,self.grade))   s = student (' Ken ', 10,60,3) S.speak ()

Achieve Results

Ken says: I'm 10 years old, I'm in Grade 3.

Multiple Inheritance: (although it is possible, but not recommended, you only need to know the order of inheritance is left to right)

#类定义class people: #定义基本属性 name = ' age = 0 #定义私有属性, private properties cannot be accessed directly outside the class __weight = 0 #定义构造方法 def __init_  _ (self,n,a,w): Self.name = n Self.age = a self.__weight = W def speak (self): print ("%s" says: I %d years old.        "% (self.name,self.age)) #单继承示例class Student (people): Grade =" Def __init__ (self,n,a,w,g): #调用父类的构函 people.__init__ (self,n,a,w) Self.grade = G #覆写父类的方法 def speak (self): print ("%s said: I'm%d years old, I'm reading grade%d"% (        Self.name,self.age,self.grade)) #另一个类, the preparation of multiple inheritance before class Speaker (): topic = ' name = ' def __init__ (self,n,t):  Self.name = n Self.topic = t def speak (self): print ("My name is%s, I am an orator, I am speaking the subject is%s"% (Self.name,self.topic))        #多重继承class sample (speaker,student): a = "def __init__ (self,n,a,w,g,t): student.__init__ (SELF,N,A,W,G) speaker.__init__ (self,n,t) test = sample ("Tim", 25,80,4, "Python") Test.speak () #方法名同, the default is to call the method of the parent class before the row in parentheses

Package:

Class Student (object):    def __init__ (self, Name, score):        self.name = name         Self.score = Scoremay = Student (" May ",")                      # Two attributes are required Peter = Student ("Peter", "May.name") print (Peter.name, peter.score) def Print_ Score (Student):                    # External function    Print_score (Student) # print ("%s ' s score is:%d"% (Student.name,student.score))             # Plain Print print ("{0} ' s score is: {1}". Format (Student.name,student.score))        Print_score (May)    Print_score ( Peter)

Polymorphic :

Class Animal (object):    def __init__ (self, name):  # Constructor of the class        Self.name = Name    def talk ( Self):        raise Notimplementederror ("subclass must implement abstract method") class Cat (Animal):    def Talk (self):        print ('%s: Meow meow! '%self.name) class Dog (Animal):    def Talk (self):        print ('%s: Wang! Wang! Wang! '%self.name) def func (obj): #一个接口, multiple morphology    obj.talk () c1 = Cat (' fluffy ') D1 = Dog (' Gray ') func (C1) func (D1)

Three main features of Python object-oriented: encapsulation, inheritance, and polymorphism (example)