What is Web Scraping?

What is Web Scraping? 

   

 

Web Scraping is known by many other names, depending on how a company likes to call it, Screen Scraping, Web Data Extraction, Web Harvesting and more, is a technique employed to extract large amounts of data from websites. Web scraping is a term for various methods used to collect information from across the Internet. Generally, this is done with software that simulates human Web surfing to collect specified bits of information from different websites. Web scraping is about downloading structured data from the web, selecting some of that data, and passing along what you selected to another process. Web scraping is essentially a form of data mining. 

Items like weather reports, auction details, market pricing, or any other list of the collected data can be sought in Web scraping efforts. Data displayed by most websites can only be viewed using a web browser. They do not offer the functionality to save a copy of this data for personal use. The only option then is to manually copy and paste the data - a very tedious job which can take many hours or sometimes days to complete. 

Web Scraping is the technique of automating this process so that instead of manually copying the data from websites, the Web Scraping software will perform the same task within a fraction of the time. The practice of Web scraping has drawn a lot of controversies because the terms of use for some websites do not allow certain kinds of data mining. Despite the legal challenges, Web scraping promises to become a popular way of collecting information as these kinds of aggregated data resources become more capable.

A web scraping software will automatically load multiple web pages one by one, and extract data, as per requirements. It is either custom built for a specific website or is one, which can be configured, based on a set of parameters, to work with any website. With the click of a button, you can easily save the data available on a website to a file in your computer. In today’s world, intelligent bots do web scraping. Unlike screen scraping, which only copies whatever the pixels display on the screen, these bots extract the underlying HTML code, as well as the data stored in a database in the background.

There are several ways to extract information from the web. Use of APIs is probably the best way to extract data from a website.  Almost all large websites like Twitter, Facebook, Google, Twitter, StackOverflow provide APIs to access their data in a more structured manner. If you can get what you need through an API, it is almost always preferred approach over web scrapping. This is because if you are getting access to structured data from the provider, why would you want to create an engine to extract the same information. There might be a few other ways like RSS feeds, but they are limited in their use and hence I am not including them in the discussion here. You can perform web scrapping in various ways, including the use of Google Docs to almost every programming language. I would resort to Python because of its ease and rich ecosystem. It has a library known as ‘BeautifulSoup’ which assists this task.

BeautifulSoup is an incredible tool for pulling out information from a webpage. You can use it to extract tables, lists, paragraph and you can also put filters to extract information from web pages.
Beautiful Soup provides a few simple methods and Pythonic idioms for navigating, searching, and modifying a parse tree: a toolkit for dissecting a document and extracting what you need. It doesn't take much code to write an application. Beautiful Soup automatically converts incoming documents to Unicode and outgoing documents to UTF-8. You don't have to think about encodings; unless the document doesn't specify an encoding and Beautiful Soup can't autodetect one.