Python design pattern object oriented programming

python design pattern object oriented


This article is based on the geek time king contest 《 Beauty of design pattern 》 Make a summary and own understanding .
When it comes to object-oriented programming , As a qualified Pythoner, It can be said that it's easy to come by . After all, Python in “ Everything is an object ” Well , If people say you don't know object-oriented programming at all , Or don't understand object orientation at all , That might get your abuse , At the end of the day , Do you really understand object oriented ? Try to answer the following questions :

  • The definition of object-oriented programming is ?Python Why object oriented programming languages ?Python Everything in the universe is an object. What is the specific form of expression ?
  • What are the four features of object orientation ? stay Python Do you have all these four points in the book ? How does this work ?

Tips : If the answer to the above question is clear 、 Very clear , That article can be skipped , If you don't feel clear , That article will give you code help more or less !

Introduction to design mode

Before we talk about object-oriented programming , Let's look at design patterns first , Design patterns are mainly composed of programming paradigms 、 Design principles 、 Design patterns constitute , The details are as follows: :
 Insert picture description here
There are a lot of concepts in Turin , But the initial grasp of , Just have a general impression .

Talk about object orientation

Object oriented history

What is object-oriented , From history , We know Python The official announcement is 1991 year ,Linux The official release is also 1991 year ,Java The official announcement is 1995 year ,Go The official announcement is 2009 year , and object-oriented The concept of historical development is :1960 Year of simula The concept of class and object is proposed for the first time , And then 70 Programming language of the s Smalltalk For the first time, object-oriented concept is used , It can be seen that the concept of object-oriented was put forward early , And with the development of software , Most subsequent languages became object-oriented languages , Is there a process oriented language ? yes , we have ,C Language is a typical process oriented language .
If you are interested, you can read Wikipedia , Learn about the history of these languages .

  • object-oriented - Wikipedia
  • Python- Wikipedia
  • Java- Wikipedia
  • Linux- Wikipedia
  • Go- Wikipedia
Object oriented concept

object-oriented , namely object-oriented, It is subdivided into object-oriented analysis 、 Object oriented design 、 object-oriented programming , namely OOA(Analysis)、OOD(Design)、OOP(programming).
If you read Wikipedia , Maybe it's still fuzzy , Let's know the key words through the figure below : Programming paradigm 、 Contains properties and methods 、 Is an instance of a class 、 The basic unit of a program 、 The purpose is to improve the expansibility and flexibility of the software . That sentence is : Object oriented is a programming paradigm , Take class and object as basic unit , Through encapsulation 、 abstract 、 polymorphic 、 Inherit these four characteristics ( Not a strong requirement ) To achieve code design , The purpose is to improve the maintainability of software 、 Extensibility 、 Reusability . Of course, the above is my personal words , Not professional , But the meaning is right .
 Insert picture description here
that Python Why is Object oriented programming language , Obviously , It provides class and object features to organize code , It also has four characteristics , Naturally, it is . But it's not an object-oriented programming language without four features ? Obviously there is no reference definition , With the development of software , Many languages are divorced from the four characteristics , such as Java Although we support inheritance , But it doesn't have much inheritance ; such as Go Just give up inheriting such features , and Java and Go There's more interface This interface feature , stay Python Li does not support , But all three are object-oriented programming languages .

Everything is object

We often talk about Python Everything is object , How to understand this sentence ? It's simple , stay Python When we want to construct a class object , It's all about inheritance object Precondition , So the judge “ Creation ” Is it the object , Just judge whether it belongs to the object , The concept of everything here is very broad , The more common ones are : Numbers 、 character string 、 Boolean 、 Function as an example , The result is as follows :
 Insert picture description here
Why are they all object types ? Let's take Boolean values as an example , adopt dir There are a lot of properties and methods in it ( Here's the picture ), Then these methods can't come out of thin air , So it's all inherited , Then it's clearer , When we use variables to refer to numbers 、 String and so on , In fact, one object after another is constructed , These objects have magical methods that enable them to support a series of operations , such as __lt__ So that it has a relatively small capacity , such as __eq__ So that it has the ability of equal judgment .
 Insert picture description here

Object oriented features

About the four characteristics : encapsulation 、 abstract 、 Inherit 、 polymorphic , You can see the summary in the figure below :
 Insert picture description here
Python Nature supports four characteristics , I used to be vague about encapsulation and abstraction , Both encapsulate abstract common code , And then provide it to other method calls , This understanding is one-sided , Because the meaning of the two is very different . Encapsulation is used to hide implementation and protect data , such as Python We often define private types in classes to be called by external programs ( Here's the picture ), Here you can see a amount to Java Of public keyword , Is to allow any call to ; and _a It is Pythoner Rio's established private method , If the pycharm such ide Wave line will be used to prompt the user that it is an illegal reference ; If it is __a, It's equivalent to Java Of private, If an external call ide It will be marked with yellow to indicate an error .
 Insert picture description here
give the result as follows :
 Insert picture description here
As for abstraction , The broad sense is to extract common code , Methods for external exposure ; The narrow sense of understanding is the concept of interface , Only the methods to be exposed are included in the interface class , Without revealing the specific implementation , That is to say “ Programming based on interfaces rather than implementation ”. It is a pity that , stay Python The interface feature is not provided in , If you're fuzzy about the interface , You can search for interface classes interface, I believe I will learn a lot of information . but Python through duck-typing And abstract base classes to implement extra abstraction , This follow-up article introduces in detail .
In addition, inheritance and polymorphism are the basic syntax , I won't elaborate here .


That's all for this article , Although it's all about the foundation , But I believe that if you finish reading it, there will still be some harvest .

本文为[one billion seven hundred and sixty-three million three hundred]所创,转载请带上原文链接,感谢

  1. 【计算机网络 12(1),尚学堂马士兵Java视频教程
  2. 【程序猿历程,史上最全的Java面试题集锦在这里
  3. 【程序猿历程(1),Javaweb视频教程百度云
  4. Notes on MySQL 45 lectures (1-7)
  5. [computer network 12 (1), Shang Xuetang Ma soldier java video tutorial
  6. The most complete collection of Java interview questions in history is here
  7. [process of program ape (1), JavaWeb video tutorial, baidu cloud
  8. Notes on MySQL 45 lectures (1-7)
  9. 精进 Spring Boot 03:Spring Boot 的配置文件和配置管理,以及用三种方式读取配置文件
  10. Refined spring boot 03: spring boot configuration files and configuration management, and reading configuration files in three ways
  11. 精进 Spring Boot 03:Spring Boot 的配置文件和配置管理,以及用三种方式读取配置文件
  12. Refined spring boot 03: spring boot configuration files and configuration management, and reading configuration files in three ways
  13. 【递归,Java传智播客笔记
  14. [recursion, Java intelligence podcast notes
  15. [adhere to painting for 386 days] the beginning of spring of 24 solar terms
  16. K8S系列第八篇(Service、EndPoints以及高可用kubeadm部署)
  17. K8s Series Part 8 (service, endpoints and high availability kubeadm deployment)
  18. 【重识 HTML (3),350道Java面试真题分享
  19. 【重识 HTML (2),Java并发编程必会的多线程你竟然还不会
  20. 【重识 HTML (1),二本Java小菜鸟4面字节跳动被秒成渣渣
  21. [re recognize HTML (3) and share 350 real Java interview questions
  22. [re recognize HTML (2). Multithreading is a must for Java Concurrent Programming. How dare you not
  23. [re recognize HTML (1), two Java rookies' 4-sided bytes beat and become slag in seconds
  24. 造轮子系列之RPC 1:如何从零开始开发RPC框架
  25. RPC 1: how to develop RPC framework from scratch
  26. 造轮子系列之RPC 1:如何从零开始开发RPC框架
  27. RPC 1: how to develop RPC framework from scratch
  28. 一次性捋清楚吧,对乱糟糟的,Spring事务扩展机制
  29. 一文彻底弄懂如何选择抽象类还是接口,连续四年百度Java岗必问面试题
  30. Redis常用命令
  31. 一双拖鞋引发的血案,狂神说Java系列笔记
  32. 一、mysql基础安装
  33. 一位程序员的独白:尽管我一生坎坷,Java框架面试基础
  34. Clear it all at once. For the messy, spring transaction extension mechanism
  35. A thorough understanding of how to choose abstract classes or interfaces, baidu Java post must ask interview questions for four consecutive years
  36. Redis common commands
  37. A pair of slippers triggered the murder, crazy God said java series notes
  38. 1、 MySQL basic installation
  39. Monologue of a programmer: despite my ups and downs in my life, Java framework is the foundation of interview
  40. 【大厂面试】三面三问Spring循环依赖,请一定要把这篇看完(建议收藏)
  41. 一线互联网企业中,springboot入门项目
  42. 一篇文带你入门SSM框架Spring开发,帮你快速拿Offer
  43. 【面试资料】Java全集、微服务、大数据、数据结构与算法、机器学习知识最全总结,283页pdf
  44. 【leetcode刷题】24.数组中重复的数字——Java版
  45. 【leetcode刷题】23.对称二叉树——Java版
  46. 【leetcode刷题】22.二叉树的中序遍历——Java版
  47. 【leetcode刷题】21.三数之和——Java版
  48. 【leetcode刷题】20.最长回文子串——Java版
  49. 【leetcode刷题】19.回文链表——Java版
  50. 【leetcode刷题】18.反转链表——Java版
  51. 【leetcode刷题】17.相交链表——Java&python版
  52. 【leetcode刷题】16.环形链表——Java版
  53. 【leetcode刷题】15.汉明距离——Java版
  54. 【leetcode刷题】14.找到所有数组中消失的数字——Java版
  55. 【leetcode刷题】13.比特位计数——Java版
  56. oracle控制用户权限命令
  57. 三年Java开发,继阿里,鲁班二期Java架构师
  58. Oracle必须要启动的服务
  59. 万字长文!深入剖析HashMap,Java基础笔试题大全带答案
  60. 一问Kafka就心慌?我却凭着这份,图灵学院vip课程百度云