Table of Contents

Assignment

Pick three of your favorite books on one of your favorite subjects. At least one of the books should have more than one author. For each book, include the title, authors, and two or three other attributes that you find interesting. Take the information that you’ve selected about these three books, and separately create three files which store the book’s information in HTML (using an html table), XML, and JSON formats (e.g. “books.html”, “books.xml”, and “books.json”). To help you better understand the different file structures, I’d prefer that you create each of these files “by hand” unless you’re already very comfortable with the file formats.

Attributes I chose,

library(RCurl)
library(XML)
library(jsonlite)
library(knitr)
#assign URLs 
html <- "https://raw.githubusercontent.com/nathanlim45/IS607/master/week9/books.html"
json <- "https://raw.githubusercontent.com/nathanlim45/IS607/master/week9/books.json"
xml <- "https://raw.githubusercontent.com/nathanlim45/IS607/master/week9/books.xml"

DATA from HTML

url_html <- getURL(html)
data_html <- readHTMLTable(url_html)
str(data_html)
## List of 1
##  $ NULL:'data.frame':    3 obs. of  5 variables:
##   ..$ title  : Factor w/ 3 levels "Harry Potter and the Sorcerer's Stone",..: 1 2 3
##   ..$ authors: Factor w/ 3 levels "C.S. Lewis, Pauline Baynes",..: 2 1 3
##   ..$ price  : Factor w/ 3 levels "10.66","22.34",..: 3 2 1
##   ..$ type   : Factor w/ 2 levels "hardcover","paperback": 2 1 2
##   ..$ pages  : Factor w/ 3 levels "320","432","784": 1 3 2
book_html <- data_html[[1]]
str(book_html)
## 'data.frame':    3 obs. of  5 variables:
##  $ title  : Factor w/ 3 levels "Harry Potter and the Sorcerer's Stone",..: 1 2 3
##  $ authors: Factor w/ 3 levels "C.S. Lewis, Pauline Baynes",..: 2 1 3
##  $ price  : Factor w/ 3 levels "10.66","22.34",..: 3 2 1
##  $ type   : Factor w/ 2 levels "hardcover","paperback": 2 1 2
##  $ pages  : Factor w/ 3 levels "320","432","784": 1 3 2
kable(book_html)
title authors price type pages
Harry Potter and the Sorcerer’s Stone J.K. Rowling 7.48 paperback 320
The Chronicles of Narnia C.S. Lewis, Pauline Baynes 22.34 hardcover 784
The Fellowship of the Ring J.R.R. Tolkien 10.66 paperback 432

DATA from JSON

url_json <- getURL(json)
data_json = fromJSON(url_json)
str(data_json)
## 'data.frame':    3 obs. of  5 variables:
##  $ title  : chr  "Harry Potter and the Sorcerer's Stone" "The Chronicles of Narnia" "The Fellowship of the Ring"
##  $ authors:List of 3
##   ..$ : chr "J.K. Rowling"
##   ..$ : chr  "C.S. Lewis" "Pauline Baynes"
##   ..$ : chr "J.R.R. Tolkien"
##  $ price  : num  7.48 22.34 10.66
##  $ type   : chr  "paperback" "hardcover" "paperback"
##  $ pages  : int  320 784 432
unlisted <- unlist(data_json[[2]])
aa<-c(unlisted[1], paste(unlisted[2], unlisted[3], sep=","), unlisted[4])
data_json$authors <- aa
str(data_json)
## 'data.frame':    3 obs. of  5 variables:
##  $ title  : chr  "Harry Potter and the Sorcerer's Stone" "The Chronicles of Narnia" "The Fellowship of the Ring"
##  $ authors: chr  "J.K. Rowling" "C.S. Lewis,Pauline Baynes" "J.R.R. Tolkien"
##  $ price  : num  7.48 22.34 10.66
##  $ type   : chr  "paperback" "hardcover" "paperback"
##  $ pages  : int  320 784 432
kable(data_json)
title authors price type pages
Harry Potter and the Sorcerer’s Stone J.K. Rowling 7.48 paperback 320
The Chronicles of Narnia C.S. Lewis,Pauline Baynes 22.34 hardcover 784
The Fellowship of the Ring J.R.R. Tolkien 10.66 paperback 432

DATA from XML

url_xml <- getURL(xml) 
xml_parsed <- xmlParse(url_xml)
list_xml<- xmlToList(xml_parsed)
library(plyr)
data_xml <- ldply(list_xml, function(x) {data.frame(x)})
book_xml <- data_xml[,2:6]
str(book_xml)
## 'data.frame':    3 obs. of  5 variables:
##  $ title  : Factor w/ 3 levels "Harry Potter and the Sorcerer's Stone",..: 1 2 3
##  $ authors: Factor w/ 3 levels "J.K. Rowling",..: 1 2 3
##  $ price  : Factor w/ 3 levels "7.48","22.34",..: 1 2 3
##  $ type   : Factor w/ 2 levels "paperback","hardcover": 1 2 1
##  $ pages  : Factor w/ 3 levels "320","784","432": 1 2 3
kable(book_xml)
title authors price type pages
Harry Potter and the Sorcerer’s Stone J.K. Rowling 7.48 paperback 320
The Chronicles of Narnia C.S. Lewis, Pauline Baynes 22.34 hardcover 784
The Fellowship of the Ring J.R.R. Tolkien 10.66 paperback 432

Conclusion

The values of each table are identical, though, their data types and forms are different depending on the data forms. So, to get the same exact three data frames and tables from each data, extra works are necessary.