How Does Data Scraping Actually Work?

By: Anna Cave
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You've probably data scraped manually before, but let's make it a whole lot easier. 

Data scraping, or web scraping, is the process of extracting data from different websites and compiling it for later use. Most companies don't offer easily downloadable data files, so if you want to collect data you will likely have to do it yourself. You've probably manually collected data before, but scraping bots take the work out of the process, despite what restrictions companies have tried to impose on their data.

So how does it actually work?

The web scraper has to first request the information from the website for a specific page and URL. Once it makes the request, the information makes it back to scraper as an HTML file. The scraper looks through that file to locate and extract the specific data we want to see. This process is called parsing, which just means the string of data from the website is broken up to reveal only the pieces of information we are interested in dealing with. When using or writing a web scraping program, the data that needs to be extracted is defined beforehand. The last step in the data scraping process is to export the data in a usable format. This usually comes in the form of a CSV for JSON file that can be easily imported into a different program for analysis. 

​Web scraping is not to be confused with web crawling, which uses an auto-bot to search content on the internet by following internal web page links. This is a crucial element for search engines like Google to function. In contrast, scrapers are designed to extract the data rather than to just search it. Scrapers and crawlers become a power team when used together, because crawlers are able to search the entire internet or website to find the data for the scraper to extract.

That’s great, but what do people use this for?

Content: This is the most obvious of all uses, but many companies use content scraping to reproduce information on their own platforms. For example, a restaurant dependent on reviews could scrape good ones from Yelp and add them to their own website to boost their image. 

Price monitoring: Ever wonder how Trivago is able to find the best hotel prices? It's because they monitor and scrape from other websites to collect prices from multiple websites before presenting you with the best one. 
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SEO: This is great for keyword research and ranking for search engines. People can see how difficult it would be to appear at the top pages for certain keywords and can adjust their SEO strategies to find relevant keywords that will allow them to show up in Google search results. 

Contact: Ever wonder why you always get spam calls about your car’s extended warranty? Web scrapers can gather information from directories and generate spam email and phone call lists.
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This is by no means a limit to the uses for web scraping. Think of any data set you might be interested in, and it’s probably been scraped. If you’re interested in trying data scraping out, we have a blog post that details some of the best tools for beginners, as well as an extensive list of scraping tools that you can check out here.