1. Object-oriented concepts
What is object-oriented
Object-oriented referred to OOP is a programming idea is summed up the experience of predecessors, how to guide programmers to write better programs
Its core is the object, the object as a basic operation unit program, the program is a set of objects, the programmer is responsible for scheduling these objects interact to accomplish the task
In object-oriented programmers in the angle changed from the operator into a specific commander
Object-oriented advantages and disadvantages of the use of scenarios
Advantages: improved scalability. When an object is changed, other objects is of no effect
Increased flexibility. For example the game, each player is free operation, rather than machine-like fixed! You can buy weapons, you can also buy Armor
Improved reusability. A defined object can be repeatedly used
Disadvantages: increased complexity of the program
We can not accurately predict the results
Be used: high scalability requirements program, usually the user-oriented, such as qq, micro-channel, and some of the frequently updated game
Process-oriented advantages and disadvantages and usage scenarios
Advantages: logical, complex problems can be streamlined, and thus of short answer
Disadvantages: poor scalability, maintainability, once the need to modify a function, it will affect the overall function
Be used: low scalability requirements of the procedure, such as the kernel, Git, calculators, etc. Once there is no need to modify the late
Note: The object-oriented and process-oriented and not good or bad, depending on the particular use to distinguish which case
2. The concept of classes and objects
And line type of object-oriented programming (OOP) in the core of the two concepts
class
Type, category, it is a set of features and acts with the same object
Objects
Is a thing of concrete existence, with words and behavior characteristics, the object is a combination of characteristics and skills
Class contains a series of objects, the object belongs to a class
In life there is a first, and then the object class, while in the program is the first class and then have the object
Conclusion: In object-oriented programming will need to consider the characteristics and behavior of objects we need to create, and then create a class of objects that belong to these characteristics and behaviors
3. How to create classes and objects
The syntax for defining classes and objects
1 # syntax definition of classes and objects 2 class class name: # Create a class 3 internal code can define his features and skills (behavior) 4 wherein variable name represents a 5 skills (acts) represented by the function . 6 . 7 concrete objects name = class name () # create a specific object
Simply create classes and objects
1 # simply create an object and a class 2 class the Person: # This is a class, although this class nothing . 3 Print (123 ) . 4 Role = ' Person ' # of people who are characteristic properties . 5 DEF EAT (Self) : # people have to eat, eat have a skill 6 return ' eAT ' 7 8 p1 = the person () # this is a subject that he is created out according to the class, the class created when the code will execute 9 Print ( p1.eat ()) # print type return value 'eat' function 10 Print (p1.role) # View class attributes
4. Find the sequence design attributes and properties
Property design
1 # Design Attribute 2 class the Person: # define a class . 3 Age = 18 is # attribute class . 4 Pass . 5 . 6 P1 = the Person () # generates an object . 7 p1.name = ' sxc ' # increase the properties of the object . 8 Print (P1 .age) . 9 Print (p1.name) 10 . 11 p1.name = ' ZZJ ' # modify attribute 12 is Print (p1.name) 13 is 14 del p1.name # delete attribute 15 16 Print (p1. __Dict__ ) # View all the properties of an object, name of the attribute is removed 17 18 Print (p1. __Class__ ) # class information access objects
Property search order
Start looking object's own property, you can not find a class to go to find. Objects ------> ------ class> parent
1 # 属性的查找顺序 2 class Person: # 定义一个类 3 age = 18 # 类的属性 4 pass 5 6 p1 = Person() # 生成一个对象 7 p1.age = 20 # 对象中的属性 8 print(p1.age) # 此时打印的是对象的属性 9 10 del p1.age #删除对象中的属性 11 print(p1.age) # 此时打印的就是类的属性了
5.初始化方法
什么是初始化方法
用于为对象的属性设置初始值的函数,__init__方法
为什么需要初始化方法
在类的实例(对象)中，一些属性是必须存在的，就可以用初始化函数来完成，如人的姓名
特点:当实例化对象时，会自动执行__init__方法，会自动将对象作为第一个参数传入。
初始化对象的属性
1 # 初始化方法 2 class Student: 3 def __init__(self,name,age,sex): # 初始化方法 4 self.name = name 5 self.age = age 6 self.sex = sex 7 8 s1 = Student('sxc', 18, 'male') 9 s2 = Student('zzj', 19, 'male') 10 print(s1.name) # 查看属性 11 print(s2.age)
注意：初始化函数不能有返回值，他只能返回None，不写return和只写return和return None都可以，但是一般默认不写
6.绑定方法之对象的绑定方法
在累中定义的函数方法默认都对象绑定方法，并且没有被任何装饰器装饰
特点:当使用对象调用该函数时会自动传入对象本身作为第一个参数
当使用类名来调用时他就是一个普通的函数，有几个参数就要传入几个参数
1 # 对象绑定方法 2 class Student: 3 def __init__(self,name,age,sex): # 初始化方法 4 self.name = name 5 self.age = age 6 self.sex = sex 7 8 def say(self): 9 print('我是%s，我的年龄是%s，我的性别是%s'%(self.name,self.age,self.sex)) 10 11 s1 = Student('sxc',18,'男') 12 s1.say() # 对象直接调用会将本身作为参数 13 14 Student.say(s1) # 类名来调用需要传入参数
7.绑定方法之类的绑定方法
用classmethod装饰器装饰的方法就是类绑定方法
特点：不管用类还是对象调用，参数的第一个必须是cls表示当前类本身,使用类名来调用,调用时会自动传入类
1 # 类绑定方法 2 class Student: 3 def __init__(self,name,age,sex): # 初始化方法 4 self.name = name 5 self.age = age 6 self.sex = sex 7 8 @classmethod 9 def say(cls,self): 10 print('我的类是%s，我是%s，我的年龄是%s，我的性别是%s'%(cls,self.name,self.age,self.sex)) 11 12 s1 = Student('sxc',18,'男') 13 s1.say(s1) # 自动传入类 14 15 Student.say(s1) # 自动传入类
8.非绑定方法(不常用)
用staticmethod装饰器装饰的方法就叫做非绑定方法，不需访问类的数据，也不需要访问对象的数据
1 # 非绑定方法 2 class Student: 3 def __init__(self,name): # 初始化方法 4 self.name = name 5 6 @staticmethod # 非绑定方法 7 def msg(): 8 print('i am a student') 9 10 s1 = Student('sxc') # 定义一个对象 11 12 Student.msg() # 类可以直接调用，不需要传参数 13 14 s1.msg() # 对象可以直接调用，不需要传参数
