What is Web Scraping?

Whenever you need to pull some data from a third party website, the first thing to check is whether the website provides an API or a mechanism to access the data programmatically.

But in case it doesn’t have an API yet but still allows users to browse and download its content, then you can access it programmatically as well. That’s, you can pull out data straight from the HTML in a structured form. Doing so is called Web Scraping, let’s see what exactly it is.

What is Web Scraping?

The technique(s) used to extract web data and save it to a file locally stored on your computer, database or spreadsheet is known as web scraping.

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The data displayed by most of the websites can only be viewed using a browser, e.g. the listings at Craigslist, yellow pages and social networks, etc.

Most of the websites don’t give you the option to save the data locally, or the option to export it to your computer. With them, you have to manually copy and paste everything (an incredibly tedious job).

With Web Scraping, you automate this process, so that you don’t have to copy and paste the data yourself manually. The scraping software does all that, within a fraction of that time. It just interacts with the website like any other browser, but rather than rendering the HTML to display the information, it saves the data to a database or a local file.

So how does it compare to data mining?

Although the names suggest the same thing, they are somewhat related processes. Simply put, Web Scraping is all about getting the data, and Data Mining is about retrieving information and valuable insight from the data.

Web Scraping can be a source for feeding data into the data mining process, but it isn’t necessary since you can have various sources for the input data.

Some Web Scraping Uses

Web Scraping has different uses for individuals and organisations alike. Everyone has different needs to gather data. Let’s take a look at some of the common scenarios, where web scraping could come in handy.

Research

Data is the central part of any research, may it be scientific, academic or marketing related. With the help of Web Scraping, you can gather mounds of data in no time.

Lead Generation

With the aid of Web Scraping, an individual or business can amass the contact details of businesses and organisations from LinkedIn or Yellow Pages. Details such as Name, Phone #, Address, Email Address, Website Address, etc. can be easily acquired by the use of a web scraper.

Market Analysis

These days, just putting your product out there is never enough. With the help of Web Scraping, you can conduct a very thorough research on your competitors and compare all the similar offerings in your category. With the aid of Web Scraping, you can quickly gather current data about everything and keep an eye on your competition.

Below are web scraping techniques I personally use to get data from my competitors Facebook pages, Twitter profiles and Blog.

Best Language for Web Scraping

The basic task in web scraping is to crawl the given website for the required data and then to extract it to your local computer. Although web scraping sounds like a daunting task, it is nothing more than a programmed script. There are a couple of great third party Web Scraping tools out there, you also can user various languages for this, here are a couple:

  • PHP
  • Ruby
  • Python
  • Perl

Although all of them get the job done, upon close inspection of various forums and blogs, it has been found that Python is the preferred language for Web Scraping.

Python Web Scraping

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Python is preferred because it has some of the most powerful and flexible frameworks for crawling and data extraction. Scrapy is one such framework. It is open source, lightweight, easy to learn and use and most of all it is extremely efficient.

There are many tutorials available on the Internet which feature Web Scraping through Scrapy and MongoDB or PostgreSQL. If you know Python, then getting the data you want without any hassle won’t be any issue for you.

Web Scraping Tools

best free web scraping tools
Now, if you don’t know how to program and still want to gather data from various sources for your research, then don’t worry. You can always get any of these amazing third party tools.

Let’s take a look at some.

Kimono Labs

With the Kimono labs, you can scrape data in two ways. You can either use their desktop version or use their chrome extension. Once you have identified the data you require, you can set when and how you want the data collection to be done. The learning curve for Kimono Labs is not very steep, and you can easily get the hang of it in just a week.

Import.io

A browser and desktop based tool, Import.io holds your hand every step of the selection process. After selecting the data, you want, it takes care of the rest. It is a tad bit more sophisticated than Kimono and can scrape multiple URLs at the same time.

I have written a very well detailed tutorial on how to scrape data using import.io from websites and blogs.

Is Web Scraping Legal?

Since most of the websites provide access to data online for public consumption then the answer to this question depends on:

  • How are you going to use the scraped data for(whether the data obtained programmatically or manually)?
  • How are you abiding or violating the target website(s) terms of use and copyrights?

Web scraping lives in the grey area between legal and illegal web scraping.You can follow ongoing discussion about this subject from these two sources.

Sources:Quora discussion,distilnetworks

Web scraping best practices

While there is no one best way to scrape data from websites, there are some few best practices you can follow.

  • You can lose connection at any time, so make sure to break down your required data into separate pieces.
  • Whenever scraping a new website, make sure to extract as much data as possible.
  • Try to be pessimistic when parsing the data, if you require an integer, then ensure that the value you got is an integer.
  • Last but not the least make sure to gather statistics from the scraped data, it always helps in the long run.

Conclusion

Just before getting on with Web Scraping, make sure to check if the terms of use of your website have anything against it. Other than that, you can use web scraping to your benefit to a great deal.

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