python-Object-oriented

1. Process oriented

-----What is called process-oriented

Process: The steps and processes for dealing with things. Core: Process

Advantages: Reduced complexity of the program disadvantages: Poor scalability

2. Object-oriented

------Object-oriented: Everything is Object core: Object

Advantages: Solve the problem of poor program extensibility

Note: In Python a variable represents a feature, a function represents a skill, and a class is a combination of a variable and a function, and an object is a combination of a variable and a method (a function that points to a class).

3. Class

Class concept: Classification, common characteristics or not a class or not, the class is to extract the same characteristics

In real life: first there are objects and classes, in the program is the first class, then there are objects

Define class: Define variable and function first letter capitalization

By an abstract thing parentheses followed by a colon produces a class, the return value is called instantiating an object, the instantiation triggers __init__ execution, the __init__ method cannot have a return value, and the instantiation tries not to invoke the Class property

classPerson : #定义一个人类 role='Chinese'# Class Property static property Def __init__ (SELF,NAME,LIFE_VALUE,AGGR): #__init__方法 dynamic Property Self.name=name #姓名 dynamic Property Self.life_value=life_value #生命值 Dynamic Properties Self.aggr=aggr #攻击力 Dynamic Properties def attack (Self,enemy): #定义了一个攻击的类属性方法 enemy.life_value=enemy.life_value-self.aggr #对象的生命值 Print ('Attack') Egg=person ('Egon', +, -#实例化这个对象 equals the execution of person.__init__ () print (egg.name) #查看属性/Call method print (Egg.life_value) print (EGG.AGGR) 

The process of instantiating is the process of class------object
The self-----automatically passes the instantiated object/instance itself to the first parameter of __init__

Interaction between programs

classPerson:role='Chinese'# Class Property static property Def __init__ (SELF,NAME,LIFE_VALUE,AGGR): #__init__方法 dynamic Property
#动态属性 Self.name=name #姓名
Self.life_value=life_value #生命值 Self.aggr=AGGR #攻击力 def attack (Self,alex): #定义一个攻击的动态属性 alex.life_value-=self.aggr #alex的生命值 #egon. Life_value-=Self.aggr #egon的生命值
# instantiating objects viewing Properties/calling methods Egon=person ('Geon', +, the) Alex=person ('Alex', -, -) print (Egon.life_value) #egon未战斗之前的生命值alex. Attack (Egon) #alex攻击egonprint (Egon.life_value) #egon战 Life after bucket print (Alex.life_value) #alex未战斗之前的生命值egon. Attack (Alex) #egon攻击alexprint (Alex.life_value) #alex战之后的生命值 classDog: #定义狗类 def __init__ (SELF,NAME,LIFE_VALUE,AGGR): #__init__方法 Dynamic Properties
#动态属性 Self.name=name #名字 self.life_value=life_value #生命值 Self.aggr=aggr #攻击力 def Bite (Self,person): #定义狗咬的技能 egon.life_value-=Self.aggr #egon的被攻击后的生命值旺财=dog ('Xiao Qiang', -, $) #实例化dog对象 # #egon与旺财大战print (egon.life_value) #狗未攻击egon之前egon的生命值旺财. Bite (Egon) #狗攻击egonprint (Egon.life     _value) #egon被攻击之后的生命值print (Wang Choi Life_value) #egon未打狗之前狗的生命值egon. Attack (Wong Choy) # #egon打狗print (Mong Choi. Life_value)    #狗被打之后的生命值 #alex and Wong Choy War print (alex.life_value) #alex没被狗攻击之前的生命值旺财. Bite (Alex) #狗攻击alexprint (Alex.life_value) #alex被咬之后的生命值print (Mong Choi Life_value) #狗没挨打之前的生命值alex. Attack (Wong Choy) #alex打狗print (Mong Choi Life_value) #狗受伤之后的生命值

4. Class namespace, instance namespace

Creating a class creates a namespace that is used to store all the names defined in the class, which are called Class name properties

The class has two properties: static property and dynamic property

• A static property is a variable that is defined directly in the class
• A dynamic property is a method defined in a class

# #面向对象名称空间问题class Person:
   Role= ' Chinese '
   passegon.role=' Indians 'print (Egon.role,id (egon.role)) Print (Alex.role,id ( Alex.role)) Print (Person.role,id (person.role)) person.role=' Indians 'print ( Egon.role,id (Egon.role)) print (Alex.role,id (alex.role)) print (Person.role,id (person.role)) # #总结: In object-oriented, if you want to invoke a property, You will not find it in the class, if you have it, call itself

5. Object-oriented combination and usage

Combination usage: In one class, an object of another class as a data property, this class is called a class combination

Example

classGrandpa: Def __init__ (self, name, age, work): Self. Name=name self. Age=age self. Work=workclassdad: Def __init__ (self, name, age, work): Self. Name=name self. Age=age self. Work=workclassson: Def __init__ (self, name, age, work, Grandpa _ name, Grandpa _ Age, Grandpa _ Work): Self. Name=name self. Age=age self. Work=work self. Grandpa=Grandpa (Grandpa _ Name, Grandpa _ Age, Grandpa _ Work) Xiao Qiang= Son ('Xiao Qiang', the,'Student','pa DAO', the,'Farmers') Print (Xiao Qiang's grandfather. Name, Xiao Qiang. Grandfather, age, Xiao Qiang. Work) Xiao Qiang= Daddy ('Big Strong', -,'Farmers') print (Xiao Qiang. Name, Xiao Qiang. Age, Xiao Qiang. Work)

Ring instance

 fromMath Import Piclasscircle:def __init__ (self,r): #动态参数 SELF.R=R #名字 Object Properties def area (self): #定义面积方法 Dynamic PropertiesreturnPI * self.r**2#计算面积并返回 def perimeter (self): #定义周长方法 Dynamic PropertiesreturnPI * self.r*2#计算周长并返回a=circle (Ten) #实例化一个圆对象print (A.area ()) print (A.perimeter ())classRing: # def __init__ (Self,r1,r2,p=3.14): Self.r1_circle=Circle (R1) self.r2_circle=Circle (R2) SELF.P=P def area (self):returnSelf.r1_circle.area ()-Self.r2_circle.area () def perimeter (self):returnSelf.r1_circle.perimeter () +Self.r2_circle.perimeter () a=ring (Ten,5) Print (A.area ()) print (A.perimeter ())

6. Object-Oriented inheritance
What do you mean, inheritance

Inheritance is a way of creating new classes in Python, where a new class can inherit one or more parent classes, which can be called a base class or a superclass, and a new class is called a derived class or subclass.

python-Object-oriented