Programmer Think

18 Threads 18.1 Processes and Threads Process: Open a program and there will be at least one process. The basic unit of resource allocation by the operating system Threads: Threads are the basic unit of CPU scheduling, and each process has at least one thread. Single thread: only one thread def funa(): print(123) def funb(): print ...

1, Selenium+Python environment construction and configuration 1.1 introduction to selenium Selenium is a web automated testing tool. Many students who study functional automation begin to prefer selenium because it has many advantages over QTP: Free, and you don't have to worry about cracking QTPCompact, it is just a package for differen ...

1, Types and tools of date and time data The modules about date, time and calendar data in Python are datatime, time and calendar **The data types in the datatime module are as follows: from datatime import***** dataUse the Gregorian calendar to store calendar dates (year, month, day)timeStore time as hours, minutes, seconds, microsecond ...

Reading guide Handsome fat school is coming again!!! I've just finished learning java recently. I'm not very proficient in inheritance and polymorphism. I found the inheritance polymorphism of python when I checked the data. I think it's interesting. I'll share it with you. I can compare it with Java. inherit What is inheritance Of c ...

Introduction to python crawler (1) Getting started with Requests Library I Requests Library 1. Installation Enter pip install requests on the cmd command line 🆗 Yes Test code #Climb Baidu home page import requests r= requests.get("http://www.baidu.com") print(r.status_code) r.encoding='utf-8' print(r.text) Operation results: ...

Article catalogue catalogue preface 1, Classifier making 1. Sample preparation 2. Sample making (1) Picture rename (2) Modify picture pixels  3. Generate resource record file  4. Generate vec file   5. Training model 2, Test classifier​ summary preface This paper introduces how to make your ...

Parsel - Crawler page parsing tool [statement]: This article is not original, but the source address of the article was not found parsel is a product of sweep and a built-in selector of sweep. It includes re, css and xpath selectors. It can extract and delete data from HTML and XML. Using this library can make the code concise. 1 installat ...

Now it seems very popular to use Python crawlers for data collection. Let's also learn about Python crawlers. Well, take a look at the python technology roadmap in Uncle Long's blog. It's very good. It all includes.... Wait, is there something missing? Carefully read the technology roadmap again... There seems to be no mention of xml, xslt and ...

Chapter 5: function usage and underlying analysis Function is also an object, which is used for memory underlying analysis In Python, "everything is an object". In fact, after executing the def definition function, the system creates the corresponding function object. We perform the following procedure and then explain: #T ...

In Python's object-oriented programming, you must first create an instance object, and then initialize the instance object__ new__ Responsible for creating instance objects__ init__ Responsible for initializing objects, which is introduced in this paper__ new__ And__ init__ And metaclasses in Python. __ new__ And__ init__ __ new__ And ...