How to use Data Packages from R

mikanebu

anuveyatsu

November 16, 2017

This tutorial demonstrates how to use Data Packages from R. We assume that you already know about Data Packages and its specifications.

Example

Let's consider "VIX - CBOE Volatility Index" data here. The VIX dataset is a key measure of market expectations of near-term volatility conveyed by S&P 500 stock index option prices introduced in 1993:

https://datahub.io/core/finance-vix

There are several ways to get data in R, but in this tutorial, we are going to use robust, high performance JSON Parser jsonlite library:

library("jsonlite")

json_file <- 'https://datahub.io/core/finance-vix/datapackage.json'
json_data <- fromJSON(paste(readLines(json_file), collapse=""))

# get list of all resources:
print(json_data$resources$name)

and you would get following table printed:

Our data is now available in different formats such as CSV, JSON, ZIP. To get it in the CSV format:

# print all tabular data(if exists any)
for(i in 1:length(json_data$resources$datahub$type)){
  if(json_data$resources$datahub$type[i]=='derived/csv'){
    path_to_file = json_data$resources$path[i]
    data <- read.csv(url(path_to_file))
    print(data)
  }
}