Setup

library(knitr)
library(kableExtra)
library(prettydoc)
library(rvest)
library(dplyr)
library(jsonlite)
library(RCurl)
library(XML)
remove(list=ls())

HTML

First, store the raw HTML file as an R object using the read_html function.

books.html <- read_html("https://raw.githubusercontent.com/aliceafriedman/DATA607_HW_WK7/master/books.html")

Then, parse the R object, html, using the html_nodes function from the rvest library.

books.html.table <- html_nodes(books.html, "table")
books.html.table <- html_table(books.html.table[1], fill = TRUE) %>% as.data.frame() %>% glimpse()

## Observations: 4
## Variables: 7
## $ Title             <chr> "How to be a Straight-A Student", "Deep Work...
## $ Auth1.Last        <chr> "Newport", "Newport", "Paul", "Dallas"
## $ Auth1.First       <chr> "Cal", "Cal", "Marilyn", "Diamond Dallas"
## $ Auth2.Last        <chr> "", "", "", "Aaron"
## $ Auth2.First       <chr> "", "", "", "Craig"
## $ Year              <int> 2006, 2016, 2003, 2005
## $ Short.Description <chr> "A guide for getting better grades in colleg...

class(books.html.table)

## [1] "data.frame"

books.html.table %>% 
  kable() %>% kable_styling(bootstrap_options = "responsive")

JSON

First, read, the JSON obects into R using the jsonlite pakage. By setting the simplifyVector option to TRUE, this will automatically create a data frame.

Unlike reading from HTML, this will also create a row number.

books.json <- read_json("https://raw.githubusercontent.com/aliceafriedman/DATA607_HW_WK7/master/books.json",  simplifyVector = TRUE)
class(books.json)

## [1] "data.frame"

books.json %>% glimpse()

## Observations: 4
## Variables: 7
## $ Title             <chr> "How to Be a Straight-A Student", "Deep Work...
## $ Auth1.Last        <chr> "Newport", "Newport", "Paul", "Page"
## $ Auth1.First       <chr> "Cal", "Cal", "Marilyn", "Diamond Dallas"
## $ Auth2.Last        <chr> "", "", "", "Aaron"
## $ Auth2.First       <chr> "", "", "", "Craig"
## $ Year              <int> 2006, 2016, 2003, 2005
## $ Short.Description <chr> "A guide for getting better grades in colleg...

books.json %>%  kable() %>% kable_styling(bootstrap_options = "responsive")

XML

Use RCurl function getURL to download the XML file from the web, then use the xmlParse function to read the XML file.

books.xml <- getURL("https://raw.githubusercontent.com/aliceafriedman/DATA607_HW_WK7/master/books.xml")
books.xml <- xmlParse(books.xml)
Title <- xpathSApply(books.xml, "//book/title", fun=xmlValue)
Year <- xpathSApply(books.xml, "//book/Year", fun=xmlValue)
Auth1.Last <- xpathSApply(books.xml, "//book/Auth1.Last", fun=xmlValue)
Auth2.Last <- xpathSApply(books.xml, "//book/Auth2.Last", fun=xmlValue)
Auth1.First <- xpathSApply(books.xml, "//book/Auth1.First", fun=xmlValue)
Auth2.First <- xpathSApply(books.xml, "//book/Auth2.First", fun=xmlValue)
Short.Description <- xpathSApply(books.xml, "//book/Short.Description", fun=xmlValue)
books.xml.df <- data.frame(Title, Year, Auth1.Last, Auth1.First, Auth2.Last, Auth2.First, Short.Description)
glimpse(books.xml.df)

## Observations: 4
## Variables: 7
## $ Title             <fct> How to Be a Straight-A Student, Deep Work, I...
## $ Year              <fct> 2006, 2016, 2003, 2005
## $ Auth1.Last        <fct> Newport, Newport, Paul, Page
## $ Auth1.First       <fct> Cal, Cal, Marilyn, Diamond Dallas
## $ Auth2.Last        <fct> , , , Aaron
## $ Auth2.First       <fct> , , , Craig
## $ Short.Description <fct> A guide for getting better grades in college...

books.xml.df %>% kable() %>% kable_styling(bootstrap_options = "responsive")

Conclusion

Although the kables look identical, the XML-to-R process generates a data frame where each column is saved as a factor. The HTML and JSON files generated a file that correctly identified character and numeric values.