What does python learn as a crawler?
This article mainly introduces "what do python do reptiles mainly learn". In daily operation, I believe that many people have doubts about what python does reptiles mainly learn. Xiaobian consulted all kinds of materials and sorted out simple and easy-to-use methods of operation. I hope it will be helpful to answer the doubts of "what do python do reptiles mainly learn?" Next, please follow the editor to study!
1. Need to know the knowledge related to html: html is a markup language that is not very difficult to learn, it is a hypertext markup language, the next application of standard general markup language. Python web crawler learning, you do not need to in-depth study of html, as long as know to master its commonly used simple tags and knowledge points on the line.
2. Urllib and urllib2: the two libraries are used when crawling web pages. In python, urllib and urllib2 are irreplaceable. Although urllib2 is more powerful than urllib, urllib has functions that urllib2 does not have.
Urllib2, you can modify the Header header by setting the Request parameter in urllib2openurl. When you visit an article, you need to change the User Agent, and you also need to use it.
Urllib supports setting coding functions. When urllib.urlencode simulates login, you often need the parameters after POST encoding. If you do not want to use a third party to log in, you need to use urllib.
3. Python scrapy:scrapy is the most widely used crawler framework, without one, but also the most mature framework, you can use mature products to avoid building wheels, you can quickly build projects.
Scrapy is also a fast, high-level screen capture and web capture framework developed by python, which is used to grab web framework and extract structured data from pages. It has a wide range of uses and can be used in data mining, monitoring and automated testing.
At this point, the study on "what python does crawler mainly learn" is over. I hope to be able to solve everyone's doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!
