Why is python called a reptile?

A reptile is usually a web crawler, a program or script that automatically grabs World Wide Web information according to certain rules. Because of python's scripting characteristics, python's ease of configuration, flexibility in the handling of characters, and python's rich network crawl modules, the two are often linked.

Before we get into the article, we need to know what a reptile is. A reptile, or web crawler, can be understood as a spider crawling on a web, and the Internet is likened to a large web, and a reptile is a spider crawling around the web, and if it encounters its own prey (the resources needed), it will crawl it down. F or example, it is crawling a web page, in which he found a road, in fact, is a hyperlink to the web page, then it can climb to another network to obtain data. Words that are not easy to understand can actually be understood in the following image:

Because of python's scripting characteristics, python's ease of configuration, flexibility in the handling of characters, and python's rich network crawl modules, the two are often linked. P ython reptile development engineers, starting with a page (usually the first page) of a web site, read the contents of the page, find other link addresses in the page, and then look for the next page through those link addresses, which loops until all the pages of the site are crawled. If you think of the entire Internet as a website, then web spiders can use this principle to crawl all the pages on the Internet.

As a programming language, Python is purely free software that is popular with programmers for its concise and clear syntax and the indentation of statements using blank characters. T o give an example: to complete a task, the c language will write a total of 1000 lines of code, java will write 100 lines, and python will only need to write 20 lines of code. With python to complete programming tasks, you write less code, more concise and readable code, read other people's code faster when a team develops, develop more efficiently, and make your work more efficient.

This is a programming language ideal for developing web crawlers, and Python's interface for crawling web documents is cleaner than other static programming languages; C ompared to other dynamic scripting languages, Python's urllib2 package provides a more complete API for accessing Web document. In addition, python has excellent third-party packages for efficient web crawling and the possible label filtering of web pages with minimal code.

The composition of the python reptile is shown below:

1, URL manager: manage the url collection to be crawled and the url collection to be crawled, transfer the url to be crawled to the web page downloader;

2, web downloader: crawl the corresponding url page, stored as a string, transmitted to the web page parser;

3, web parser: parsing valuable data, stored down, while supplementing url to URL manager.

Python's workflow, on the other hand, looks like this:

(Python reptiles use the URL manager to determine whether a URL is to be crawled, and if it is to be crawled, pass it to the downloader through the scheduler, download the URL content, and pass the URL content through the scheduler to the parser, parse the URL content, and pass value data and a new URL list through the scheduler to the application, and output value information.) )

Python is a programming language ideal for developing web crawlers, offering modules such as urllib, re, json, pyquery, and many molding frameworks, such as the Scrapy framework, the PySpider reptile system, and so on, which is very simple and convenient in itself so it is the preferred programming language for web crawlers!

Recommended courses: Python3 Getting Started, Python3 Advanced