Shulou(Shulou.com)06/02 Report--

Today, I will talk to you about the example analysis of Huawei's official analysis of what a Python crawler is. Many people may not know much about it. In order to make you understand better, the editor has summarized the following for you. I hope you can get something according to this article.

According to Huawei's official Chinese news, Huawei China posted a message "Xiaobai, let the Python crawler be your good helper". The article introduces in detail the working principle of the Python crawler. Let's take a look.

With the advent of the information society, people are no longer unfamiliar with the word web crawler. But what is a crawler and how to use a crawler to serve itself sounds a little high in the ICT technology rookie. Don't worry, the following article takes you to the world of crawlers, so that even if you are an ICT technology rookie, you can also know how to use Python crawlers to capture pictures efficiently.

What is a dedicated crawler?

Web crawler is an automated program that grabs data and information from the Internet. If we compare the Internet to a large spider's web, the data is stored at each node of the spider's web, and the crawler is a small spider (program) that grabs its prey (data) along the web.

The crawler can carry out various operations such as exception handling and error retry in the crawling process to ensure that the crawling runs continuously and efficiently. It is divided into general crawler and special crawler. The general crawler is an important part of the crawl engine crawling system, and its main purpose is to download the web pages on the Internet locally to form a mirror backup of Internet content; the special crawler mainly provides services for a specific group of people. the crawled target web pages are located in the pages related to the topic, saving a lot of server resources and bandwidth resources. For example, in order to obtain data from a certain vertical field or have a clear need for retrieval, it is necessary to filter out some useless information.

How reptiles work

A crawler can get a large number of pictures from a web page based on the information we provide. how does it work?

The first job of the crawler is to obtain the source code of the web page, which contains some useful information of the web page; then the crawler constructs a request and sends it to the server, which receives the response and parses it. In fact, getting a web page-analyzing the source code of a web page-extracting information is a trilogy of crawlers' work. How to extract information? The most common approach is to use regular expressions. Web page structure has certain rules, and there are some libraries that extract web page information according to web node attributes, CSS selector or XPath, such as Requests, pyquery, lxml, etc., using these libraries, you can efficiently and quickly extract web page information, such as node attributes, text values, etc., and can be simply saved as TXT text or JSON text, which can be saved to databases, such as MySQL and MongoDB, or to remote servers. Such as operating with the help of SFTP. Extracting information is a very important role of the crawler, which can make the messy data organized so that we can process and analyze the data later.

After reading the above, do you have any further understanding of Huawei's official analysis of what is the example analysis of Python crawler? If you want to know more knowledge or related content, please follow the industry information channel, thank you for your support.

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