With the development of information technology, I think everyone is no stranger to the word crawler, and the Python language is a programming language very suitable for the crawler field, then do you know what a Python crawler is? What can it do? Xiaobian for you Explain.
What is a dedicated crawler?
A web crawler is an automated program that crawls data and information from the Internet. If we compare the Internet to a large spider web, the data is stored in each node of the spider web, and the crawler is a small spider crawling along the web. Take your own data.
The crawler can perform various exception handling, error retry and other operations during the crawling process to ensure that crawling continues to run efficiently. It is divided into general crawlers and special crawlers. General crawlers are an important part of the search engine system. The main purpose is to download web pages on the Internet to the local area to form a mirror backup of Internet content; special crawlers are for a specific group of people Provide services and locate the crawled target webpages in pages related to the subject, saving a lot of server resources and bandwidth resources.
How does the crawler work?
The crawler's first job is to obtain the source code of the webpage, which contains some useful information of the webpage; then the crawler constructs a request and sends it to the server, and the server receives the response and parses it out. In fact, obtaining webpages-analyzing the source code of webpages-extracting information is the trilogy of crawler work.