Assignment Description: We are to pick three of our favorite books and store 4 to 5 of the books’ attributes in 3 different formats, HTML, XML and JSON. We will write R code to load the information from each of the three sources into separate R data frames.
I have decided to pick 3 foreign books and created a file for each format with the following attributes:
Title, Author, Year Published, Country, Original Title.
I wrote the files using notepad and saved all three files in a github repository, which is where I will be extracting the data from.
I first load the libraries that I will be using to extract and parse the HTML file. I used Rcurl to facilitate the extraction process from the web, DT to create a table and XML to read my HTML file:
#load packages
library(RCurl)## Loading required package: bitopslibrary(DT)
library(XML)
#parse file from web
htmlURL <- getURL("https://raw.githubusercontent.com/marioipena/Assignment5DATA607/master/ForeignBooks.html")
books_html <- htmlParse(htmlURL)
#create data frame
books_html_table <- readHTMLTable(books_html, stringsAsFactors = FALSE)
books_html_table <- books_html_table[[1]]
#view
datatable(books_html_table)#structure
str(books_html_table)## 'data.frame': 3 obs. of 5 variables:
## $ Title : chr "The Alchemist" "The Little Prince" "Good Omens"
## $ Author : chr "Paulo Coelho" "Antoine de Saint-Exupery" "Neil Gaiman, Terry Pratchett"
## $ Year Published: chr "1988" "1943" "1990"
## $ Country : chr "Brazil" "France" "England"
## $ Original Title: chr "O Alquimista" "Le Petit Prince" "Good Omens"The libraries that I will be using to extract and parse the XML file are the same as the ones in our previous example. I used Rcurl to facilitate the extraction process from the web, DT to create a table and XML to read my XML file:
xmlURL <- getURL("https://raw.githubusercontent.com/marioipena/Assignment5DATA607/master/ForeignBooks.xml")
books_xml <- xmlParse(xmlURL)
#create data frame
books_xml_table <- xmlToDataFrame(books_xml, stringsAsFactors = FALSE)
#view
datatable(books_xml_table)#structure
str(books_xml_table)## 'data.frame': 3 obs. of 5 variables:
## $ Title : chr "The Alchemist" "The Little Prince" "Good Omens"
## $ Author : chr "Paulo Coelho" "Antoine de Saint-Exupery" "Neil Gaiman, Terry Pratchett"
## $ YearPublished: chr "1988" "1943" "1990"
## $ Country : chr "Brazil" "France" "England"
## $ OriginalTitle: chr "O Alquimista" "Le Petit Prince" "Good Omens"The libraries that I will be using to extract and parse the JSON file are the same as the ones in our previous example, with the exception of RJSONIO. I used Rcurl to facilitate the extraction process from the web, DT to create a table and RJSONIO to read my XML file:
#load package
library(RJSONIO)
#parse file from web
jsonURL <- getURL("https://raw.githubusercontent.com/marioipena/Assignment5DATA607/master/ForeignBooks.json")
books_json <- fromJSON(jsonURL)
#create data frame
books_json_table <- do.call("rbind", lapply(books_json[[1]], data.frame, stringsAsFactors = FALSE))
#view
datatable(books_json_table)#structure
str(books_json_table)## 'data.frame': 3 obs. of 5 variables:
## $ Title : chr "The Alchemist" "The Little Prince" "Good Omens"
## $ Author : chr "Paulo Coelho" "Antoine de Saint-Exupery" "Neil Gaiman, Terry Pratchett"
## $ Year.Published: num 1988 1943 1990
## $ Country : chr "Brazil" "France" "England"
## $ Original.Title: chr "O Alquimista" "Le Petit Prince" "Good Omens"As you can see all three data frames look pretty much identical with a few differences. For the XML file, I had to write “Year Published” and “Original Title” together in order for the file to run properly. Additionally, even though the JSON file allowed me to write “Year Published” and “Original Title” separately and not have any issues when running, when printed here on R, we can see that the space in between was replaced with a dot (.).
Lastly, we can see from looking at the structures of each table that all the fields are read as characters except for “Year Published” in the JSON file, which is read as a number.