What is a Python crawler?

It is a program that automatically extracts web pages. It downloads web pages from the World Wide Web for search engines.

A web crawler is a program that automatically extracts web pages. It downloads web pages from the World Wide Web for search engines and is an important component of search engines. The traditional crawler starts from the URL of one or several initial web pages and obtains the URL on the initial web page. During the process of crawling the web page, it continuously extracts new URLs from the current page and puts them into the queue until certain stopping conditions of the system are met.

The web page URL to be crawled next will be selected from the queue according to a certain search strategy, and the above process will be repeated until a certain condition of the system is reached. In addition, all web pages captured by crawlers will be stored by the system, subjected to certain analysis, filtering, and indexing for subsequent query and retrieval.

Extended information:

Relevant requirements for web crawlers:

1. The Python standard library provides system management, network communication, text processing, and database interfaces , graphics system, XML processing and other additional functions.

2. Crawl pages according to the depth of the web content directory. Pages at a shallower directory level are crawled first. When the crawling of pages in the same level is completed, the crawler will go to the next level and continue crawling. ?

3. Text processing, including text formatting, regular expression matching, text difference calculation and merging, Unicode support, binary data processing and other functions.

Baidu Encyclopedia-Web Crawler