Book Image

R Web Scraping Quick Start Guide

By : Olgun Aydin
Book Image

R Web Scraping Quick Start Guide

By: Olgun Aydin

Overview of this book

Web scraping is a technique to extract data from websites. It simulates the behavior of a website user to turn the website itself into a web service to retrieve or introduce new data. This book gives you all you need to get started with scraping web pages using R programming. You will learn about the rules of RegEx and Xpath, key components for scraping website data. We will show you web scraping techniques, methodologies, and frameworks. With this book's guidance, you will become comfortable with the tools to write and test RegEx and XPath rules. We will focus on examples of dynamic websites for scraping data and how to implement the techniques learned. You will learn how to collect URLs and then create XPath rules for your first web scraping script using rvest library. From the data you collect, you will be able to calculate the statistics and create R plots to visualize them. Finally, you will discover how to use Selenium drivers with R for more sophisticated scraping. You will create AWS instances and use R to connect a PostgreSQL database hosted on AWS. By the end of the book, you will be sufficiently confident to create end-to-end web scraping systems using R.
Table of Contents (7 chapters)

Web Scraping with rvest

All the data we need today is already available on the internet, which is great news for data scientists. The only barrier to using this data is the ability to access it. There are some platforms that even include APIs (such as Twitter) that support data collection from web pages, but it is not possible to crawl most web pages using this advantage.

Before we go on to scrape the web with R, we need to specify that this is advanced data analysis, data collection. We will use the Hadley Wickham's method for web scraping using rvest. The package also requires selectr and xml2 packages.

The way to operate the rvest pole is simple and straightforward. Just as we first made web pages manually, the rvest package defines the web page link as the first step. After that, appropriate labels have to be defined. The HTML language edits content using various tags...