Web scraping
By: Jyoti Kalra
Tags: Artificial Intelligence, Job Search, Web Scraping, Machine Learning, Data Science

Web scraping, web harvesting, or web data extraction is data scraping used for extracting data from websites. Web scraping software may access the World Wide Web

What is web scraping?

Data data everywhere, but very difficult to use. Tons of data is available on web but how much of it is in usable form?

Why do we need to scrape the data?

We need to convert the unstructured data into structured form which cannot be done by copy-pasting data from web. If we wish to take data from 100 pages it is time taking and repetitive task. Data needs to be pulled from web and stored in your computer for further analysis. We need constellation from the galaxy.

This data can be used for the various studies:

Competitor data analysis Price Intelligence Social Website Market Research/Analysis Source of alternative/supporting data Search Jobs- you can sort the jobs by experience and salary, filter the job location and much more. Benefit of having this data is that you don’t have to visit multiple pages.

You can browse through multiple web sites and store the data in single excel sheet. This data can be used for the research and development.

Can we copy data from web-just like that?

No, You need to crawl and create the silk-just like a silk worm. But you will be stopped. Web site owners can setup few limitations on crawling of the site. Based on the these limitations, web robot who goes to scrape the data from web site will be stopped.

These restrictions are created for SEO-Search Engine optimization, if you are the website owner you need to setup robots.txt file which contains directives from search engine for crawling specific parts of your website, and to prevent duplicate content. robots.txt file plays a big role in SEO

Steps to Crawl:

Below are the simple steps along with the code to get the data from the website.

Step 1)Use the best in class python library- Beautiful Soup

Step 2)robotexclusionrulesparser is the library which is useful for parsing the robots.txt file available at the website. This will help you in passing through all the restrictions and finally you can use the information which is required.

Step 3)Below is the code to import various libraries and access the page you would like to open.

Step 4)You can now choose to keep website link in the variable. By doing this step you can get data from multiple pages in one go. This link can be passed to the variable ‘page’ in this code

Web scraping is a task that has to be performed responsibly so that it does not have a detrimental effect on the sites being scraped.

‘BE GOOD AND FOLLOW A WEBSITE’S CRAWLING POLICIES’

Best practices to follow for scraping without getting blocked

Initiate the requests through Proxies and rotate them as needed Follow all the instructions of Robots.txt Keep adequate sleep time for a fast running server Check if website is changing the layouts Rotate user agent and corresponding HTTP Request Headers between requests.

Now, you will get the desired data in the excel sheet and this data can be used for the analysis.

To know more about best practices visit:https://www.scrapehero.com/how-to-prevent-getting-blacklisted-while-scraping/

LinkedIn profile: linkedin.com/in/kalrajyoti