Shulou(Shulou.com)06/03 Report--

In this issue, the editor will bring you about what the python language is and how the Python crawler architecture is composed. The article is rich in content and analyzes and describes for you from a professional point of view. I hope you can get something after reading this article.

In the eyes of most people, python is only used to do web crawlers. In fact, python has its strong place, today let's find out why python is so popular, what can it do?

What is python language for?

1. Cloud computing PYTHON language is the most popular language in cloud computing, and OpenStack is a typical application.

2. Compared with the modular design of php\ ruby, WEB front-end development python is very convenient for functional expansion; a large number of excellent web development frameworks have been formed over the years, and are constantly iterated; such as the current excellent full-stack django, framework flask, all inherit the simple and clear style of python, high development efficiency, easy maintenance, and good integration with automated operation and maintenance. Python has become the de facto standard in the field of automated operation and maintenance platform; many large websites are developed by Python, Youtube,   Dropbox,   Douban.

3. Artificial intelligence applications based on big data's analysis and deep learning have essentially been unable to leave the support of python. At present, the world's excellent artificial intelligence learning frameworks, such as Google's TransorFlow  , FaceBook's PyTorch and the open source community's neural network library Karas, are implemented with python. Even Microsoft's CNTK (Cognitive Toolkit) fully supports Python, and Microsoft's Vscode already supports Python as a first-level language.

4. The system operation and maintenance project Python is very close in integration with the operating system and management. At present, all linux distributions have python, and there are a large number of modules that can be used for the related management functions in linux, such as the current mainstream automatic configuration management tool: SaltStackAnsible (currently RedHat). At present, in almost all Internet companies, the standard configuration of automated operation and maintenance is python+Django/flask. In addition, openstack, which is already a standard in virtualization management, is implemented by python, so Python is a necessary skill for all operation and maintenance personnel.

5. Financial management analysis quantitative transaction, financial analysis, in the field of financial engineering, Python language is not only in use, but also most frequently used, and its importance is increasing year by year. The reason: as a dynamic language, Python has a clear and simple language structure, rich libraries, mature and stable, scientific calculation and statistical analysis are very powerful, and its production efficiency is much higher than that of cPerson.It is especially good at policy back testing.

6. Compared with other interpretive languages, big data analyzes that the biggest feature of Python language is its huge and active scientific computing ecology, which has quite perfect and excellent libraries in data analysis, interaction and visualization (python data analysis stack: Numpy   Pandas   ScipyMatplotlipIpython), and has formed its own unique Python distribution for scientific computing, which has been rapidly evolving and improving in recent years. It forms a strong alternative to the traditional data analysis language such as R   MATLAB   SAS   Stata.

Python crawler can do a lot of things, such as search engine, data collection, advertising filtering, etc., Python crawler can also be used for data analysis, can play a huge role in data crawling!

Composition of Python crawler architecture

1. URL manager: manages the url collection to be crawled and the crawled url collection, and transmits the url to be crawled to the web downloader

two。 Web page downloader: crawl the web page corresponding to url, store it as a string, and send it to the web page parser

3. Web page parser: parses valuable data, stores it, and complements url to URL manager.

How Python crawler works

Through the URL manager, the Python crawler determines whether to climb the URL, if it needs to climb the URL, passes it to the downloader through the scheduler, downloads the URL content, and transmits it to the parser through the scheduler, parses the URL content, and passes the value data and the new URL list to the application through the scheduler, and outputs the value information.

The common frameworks used by Python crawlers are:

Grab: Web crawler framework (based on pycurl/multicur)

Scrapy: Web crawler framework (based on twisted), does not support Python3

Pyspider: a powerful crawler system

Cola: a distributed crawler framework

Portia: visual crawler based on Scrapy

Restkit:Python 's HTTP resource kit. It allows you to easily access HTTP resources and build objects around it

Demiurge: a crawler micro-framework based on PyQuery.

Python crawler has a wide range of applications, and it is in the dominant position in the field of web crawler. The application of Scrapy, Request, BeautifuSoap, urlib and other frameworks can achieve the function of crawling freely, as long as you have the idea of data crawling, Python crawler can be achieved!

The above is what the editor shares with you what the python language is and how the Python crawler architecture is composed. If you happen to have similar doubts, please refer to the above analysis to understand. If you want to know more about it, you are welcome to follow the industry information channel.

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