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ceremonial Python Column No 36 piece , Classmate, stop , Don't miss this from 0 The beginning of the article ！

Previously, I wrote other functions such as file reading and file processing , It uses os library .

I wanted to share os library , Finding this library may be difficult for beginners , So we'll talk later at the right time , Because a lot of file system operations are designed , More biased Linux Operation and maintenance .

Let's look at face object programming first , That's what many people talk about OOP（Object-oriented Programming)

What is object oriented programming ？

Have we heard of process oriented , It's better to compare them together .

Simply understand , Process oriented is to solve all files with functions , Simple and crude ！

Object oriented is Process oriented programming And then there was , Without object-oriented programming, many programs are not developed as usual .

object-oriented , Also use the function , But there is an extra net , This net puts one or more functions , Associated with data , Then it is called a kind of thing , That is, in the program ‘ class ’（class）

Defining classes , Feel it from the specific code ！

object-oriented programming , The first concept put forward is ‘class’, class ：

# So that's one class The definition code of ：
class hello_class():
    pass
    
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And then through class_name() This is used to call the production object .

Upgrade the code a little , Let's see. ：

class hello_class():
    pass

# Output class information 
print(hello_class)
print(type(hello_class))
# Create instance object of class 
print(hello_class())
print(type(hello_class()))
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Just to add a little bit ：

print The function outputs the result of the class object ： Usually <'class full name ‘ object at id Serial number >

Here are the results ：

Here we add new knowledge points ： Class instance object , Usually say directly , example .

The instance is class The object of production , All some hello_class Type of object （ adopt type Function to obtain ） Must be hello_class.

Observation of multiple classes and objects

After reading a class , Let's look at the comparison between the two classes , The results are the same .

The following is the definition of the two classes and the code display of the generated object ：

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Time : 2021/11/15 11:58  Afternoon 
# @Author : LeiXueWei
# @CSDN/Juejin/Wechat:  Lei Xuewei 
# @XueWeiTag: CodingDemo
# @File : __init__.py.py
# @Project : hello


class student(object):
    def __init__(self):
        print("hello, I am student")


class programmer(object):
    def __init__(self):
        print("hello, I am programmer")


class student(object):
    def __init__(self):
        print("hello, I am student")


class programmer(object):
    def __init__(self):
        print("hello, I am programmer")


s1 = student
print(s1)
p1 = programmer
print(p1)
s11 = student
print(s11)
p11 = programmer
print(p11)

print("*" * 16)
#  Create objects 
s2 = student()
print(s2)
p2 = programmer()
print(p2)

#  Create objects 
s3 = student()
print(s3)
p3 = programmer()
print(p3)
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Explain a little ：

s1 and p1 The printout of these two variables is ‘class’ Type of .
s11 and p11 The printout of these two variables is ‘class’ Type of , however s1 Follow s11,p1 Follow p11 It is the same. .
s2 and p2 The printout of these two variables is 'object' Type of .
s3 and p3 The printout of these two variables is 'object' Type of .\

Here are the results ：

Come here , Everyone should know class and object What's the difference

class ： Describes the fixed relationship between functions and attributes （ Class instance ） object ： A living individual based on this fixed relationship , its id It is changing. .

Add the properties of the class （ Data section ）

The school committee defined a student class , And created two student objects .

Directly copy and run the following code ：

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Time : 2021/11/15 11:58  Afternoon 
# @Author : LeiXueWei
# @CSDN/Juejin/Wechat:  Lei Xuewei 
# @XueWeiTag: CodingDemo
# @File : __init__.py.py
# @Project : hello


class student(object):
    def __init__(self, name):
        self.name = name

    def get_name(self):
        return self.name

    def set_name(self, name):
        self.name = name

    def study(self):
        print(f"{self.name} :  study hard , Day day up ！")



s1= student(" The small white ")
print(s1)
print(s1.get_name())
print(s1.study())

s2 = student(" Student fans of the School Committee : Ha ha ha ")
print(s2)
print(s2.get_name())
print(s2.study())
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We saw their id It's always different （ Run a few times to see ）.

Then every student has a name attribute （ Carry name data ）, And three function properties （ Respectively used to get the name , Change of name , Study ）.

Then we called each student's study function , Output their learning status .

summary

Python Simple design of language , Makes object-oriented programming very simple , It's easy to define and get objects .

The code above is very simple , But you can feel the presentation of classes and objects well , Practice more .

by the way , like Python Friend, , Please pay attention to Python Basic column or Python From getting started to mastering the big column

Continuous learning and continuous development , I'm Lei Xuewei ！
Programming is fun , The key is to understand the technology thoroughly .
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