Object Oriented (i)

Catalogue1. Classes and Objects 2. Object-oriented 3.self what the hell? 4. Constructors 5. Encapsulation 6. Inheritance and multiple inheritance one, classes, and objects

#创建类, class named Mailclass mail:# "method"    def email (self,mail,neirong):        print ("To:", mail, "\ n content:", Neirong)        return True                              #如果不定义返回值, the default is none# "call" obj = Mail ()                                     #创建对象, object name Objobj.email (' Admin ', ' Hello, please find the attachment form. ')          #通过对象执行方法注: When you execute obj = Mail (), the class object pointer points obj to class mail.

Second, object-oriented

Concept: Object-oriented is a programmatic approach that requires classes and objects to be implemented.

A class is a template that contains several functions that implement some functions in a template.

An object is an instance created from a class that can execute functions in a class through an instance object.

Object-oriented is also the classification and encapsulation of functions or things.

Object-oriented three major features:

Encapsulation, inheritance, polymorphism

1. Functional programming and object-oriented programming comparison

Function-Type programming

def add (host,username,passwd):    print (HOST,USERNAME,PASSWD, "add") def remove (host,username,passwd):    print ( HOST,USERNAME,PASSWD, "remove") def modify (host,username,passwd):    print (HOST,USERNAME,PASSWD, "modify") def Select (HOST,USERNAME,PASSWD):    print (HOST,USERNAME,PASSWD, "select") #执行函数add (' host.com ', ' admin ', ' 123 ') remove (' host.com ', ' admin ', ' 123 ') modify (' host.com ', ' admin ', ' 123 ') Select (' host.com ', ' admin ', ' 123 ')

Object-Oriented Programming

Class SQLHelper:    def fetch (self, SQL):        print (obj1.hhost)        print (Obj1.uuserane)        print (OBJ1.PWD)    def create (self, SQL):        pass def-    remove (self, nid):        pass    def modify (self, name):        Passobj1 = SQLHelper () #以下定义的值被封装到对象obj1中, which can be called directly in a class. Obj1.hhost = "c1.salt.com" Obj1.uuserane = "Alex" obj1.pwd = "123" Obj1.fetch ("select * from A") 2. Under what circumstances is it appropriate to use object-oriented?  when some functions have the same parameters, object-oriented methods can be used to encapsulate the value of the parameter once to the object, and then to the object to take a value.

Third, what is self?

Self is a parameter that Python automatically assigns to a value. Which object executes the method, and who is self. Obj1.fetch (...)               Self = obj1

　　

Object Oriented (i)