Book Image

R Data Analysis Cookbook - Second Edition

By : Kuntal Ganguly, Shanthi Viswanathan, Viswa Viswanathan
Book Image

R Data Analysis Cookbook - Second Edition

By: Kuntal Ganguly, Shanthi Viswanathan, Viswa Viswanathan

Overview of this book

Data analytics with R has emerged as a very important focus for organizations of all kinds. R enables even those with only an intuitive grasp of the underlying concepts, without a deep mathematical background, to unleash powerful and detailed examinations of their data. This book will show you how you can put your data analysis skills in R to practical use, with recipes catering to the basic as well as advanced data analysis tasks. Right from acquiring your data and preparing it for analysis to the more complex data analysis techniques, the book will show you how you can implement each technique in the best possible manner. You will also visualize your data using the popular R packages like ggplot2 and gain hidden insights from it. Starting with implementing the basic data analysis concepts like handling your data to creating basic plots, you will master the more advanced data analysis techniques like performing cluster analysis, and generating effective analysis reports and visualizations. Throughout the book, you will get to know the common problems and obstacles you might encounter while implementing each of the data analysis techniques in R, with ways to overcoming them in the easiest possible way. By the end of this book, you will have all the knowledge you need to become an expert in data analysis with R, and put your skills to test in real-world scenarios.
Table of Contents (14 chapters)

Reading JSON data

Several RESTful web services return data in JSON format, in some ways simpler and more efficient than XML. This recipe shows you how to read JSON data.

Getting ready

R provides several packages to read JSON data, but we will use the jsonlite package. Install the package in your R environment, as follows:

> install.packages("jsonlite")

If you have not already downloaded the files for this chapter, do it now and ensure that the students.json files and student-courses.json files are in your R working directory.

How to do it...

Once the files are ready, load the jsonlite package and read the files as follows:

  1. Load the library:
> library(jsonlite) 
  1. Load the JSON data from the files:
> dat.1 <- fromJSON("students.json") 
> dat.2 <- fromJSON("student-courses.json")
  1. Load the JSON document from the web:
> url <- "" 
> jsonDoc <- fromJSON(url)
  1. Extract the data into data frames:
> dat <- jsonDoc$list$resources$resource$fields 
> dat.1 <- jsonDoc$list$resources$resource$fields
> dat.2 <- jsonDoc$list$resources$resource$fields
  1. Verify the results:
> dat[1:2,] 
> dat.1[1:3,]
> dat.2[,c(1,2,4:5)]

How it works...

The jsonlite package provides two key functions: fromJSON and toJSON.

The fromJSON function can load data either directly from a file or from a web page, as the preceding steps 2 and 3 show. If you get errors in downloading content directly from the web, install and load the httr package.

Depending on the structure of the JSON document, loading the data can vary in complexity.

If given a URL, the fromJSON function returns a list object. In the preceding list, in step 4, we see how to extract the enclosed data frame.