How to optimize the performance of Python programs

　
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1. Optimization algorithm time complexity The time complexity of the algorithm has the greatest impact on the execution efficiency of the program. In Python, you can optimize the time complexity by selecting an appropriate data structure. For example, the time complexity of list and set to find an element is O (n) and O (1) respectively. Different scenarios have different optimization methods. Generally speaking, there are divide and conquer read the whole passage

Using SecureCRT Skillfully to Automate the Complicated SSH Login Process

　
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Previously, the company's servers were connected directly through SSH in SecureCRT, but recently, the company was considering security audit, and added a layer of bastion machine in front of all servers, and the password used kerberos centralized authorization authentication. This is the problem. Although the purpose of security audit has been achieved, the efficiency of logging in the server has been greatly reduced. Click the mouse once before read the whole passage

Teach you how to check whether the Linux machine has been invaded

　
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With the growing popularity of open source products, as a Linux operation and maintenance engineer, it is very important to be able to clearly identify whether the abnormal machine has been invaded. Combining my work experience, I have sorted out several common cases of machine blackout for reference background information: the following cases are viewed in the CentOS 6.9 system, and other Linux distributions are similar to 1. Intrusion read the whole passage

Sort out Python object-oriented knowledge points

　
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Object oriented technology introduction class: used to describe the collection of objects with the same properties and methods. It defines the properties and methods common to each object in the collection. An object is an instance of a class. Class variables: class variables are common in the entire instantiated object. Class variables are defined in the class and outside the function body. Class variables are not usually used as instance variables read the whole passage

Python 3 crawler captures NetEase Cloud music hot reviews

　
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I just started python crawler a while ago. I haven't written python for about half a month, and I almost forget it. So I'm going to write a simple crawler trainer. I think the best feature of NetEase Cloud Music is its accurate song recommendation and unique user comments, so I wrote this crawler that captures the hot reviews in NetEase Cloud Music Hot Song List. I'm also a beginner crawler. What's your meaning read the whole passage

Wu Zhihong - How to develop the golden eye in interpersonal relationships

　
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Brief introduction to the author: Mr. Wu Zhihong is a psychologist and has published many influential books. He has been engaged in psychological consultation for 10 years and has accumulated more than 6000 hours. He has rich psychological knowledge and is also an experienced psychological consultant. He has both modular knowledge and vivid cases. 1. Look at the problem from the perspective of relationship. If you have a relationship perspective, you will become different read the whole passage

Analysis of MySQL master slave replication principle

　
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Why do you want to be the master and slave of replication? 1. In a system with complex business, there is a scenario where a SQL statement needs to lock a table, which results in the temporary inability to use read services. This will greatly affect the running business. Use master-slave replication, and let the master database be responsible for writing and the slave database be responsible for reading. In this way, even if the master database has a situation of locking a table, the normal operation of the business can be ensured through the read slave database. 2. Make Data read the whole passage

Teach you to understand the difference and relationship between web server, application server, web container and reverse proxy server

　
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We know that people with different skin colors have very different appearances, and it is difficult to identify twins. Interestingly, Web servers/Web containers/Web application servers/reverse proxies are a bit like quadruplets, which often appear together on the network. This article will show readers how to distinguish these four similar concepts.   1. Understand web server, application server, web container, reverse proxy in one article read the whole passage

Http protocol details

　
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HTTP hypertext transport protocol http uses connection oriented TCP as the transport layer protocol. Http itself has no connection. The request message CRLF is the request message with the carriage return and line feed method of GET and the request message with the method of GET and the request message with the method of POST OPTIONS: This method can read the whole passage