Untitled

library(XML)
library(RCurl)

## Loading required package: bitops

library(rjson)
library(RJSONIO)

## 
## Attaching package: 'RJSONIO'
## 
## The following objects are masked from 'package:rjson':
## 
##     fromJSON, toJSON

library(jsonlite)

## 
## Attaching package: 'jsonlite'
## 
## The following objects are masked from 'package:RJSONIO':
## 
##     fromJSON, toJSON
## 
## The following objects are masked from 'package:rjson':
## 
##     fromJSON, toJSON
## 
## The following object is masked from 'package:utils':
## 
##     View

Processing the HTML file

#File location
url4html <-"https://raw.githubusercontent.com/fangseup88/Assignment_Week7/master/books.html"

#Getting the data file
file4html <- getURL(url4html)

#Create dataframe 
df4html <-  data.frame(readHTMLTable(file4html))

Processing XML file

url4xml <-"https://raw.githubusercontent.com/fangseup88/Assignment_Week7/master/books.xml"
#Getting the data file
file4xml <- getURL(url4xml)
#Create dataframe 
intermxml <- xmlTreeParse(file4xml)
df4xml<-data.frame(xmlToList(intermxml, addAttributes=FALSE))

Processing JSON file

#Location of the file
url4json <-"https://raw.githubusercontent.com/fangseup88/Assignment_Week7/master/books.json"
#Getting the data file
file4json <- getURL(url4json)
#Create dataframe 
df4json <- data.frame(fromJSON(file4json))

Print the results

#data frame for HTML
print(df4html)

##                                                                                                      NULL.Title
## 1 Fundamentals of Machine Learning for Predictive Data Analytics: Algorithms, Worked Examples, and Case Studies
## 2                                         Machine Learning: Hands-On for Developers and Technical Professionals
## 3                                                                                       Machine Learning with R
##                                    NULL.Author.s. NULL.Publication.Date
## 1 John D. Kelleher, Brian Mac Namee, Aoife D'Arcy            2015-07-24
## 2                                      Jason Bell           N2014-11-03
## 3                                     Brett Lantz            2013-10-25
##                          NULL.Publisher
## 1 Massachusetts Institute of Technology
## 2               John Wiley and Sons Inc
## 3                      Packt Publishing

#data frame for XML
print(df4xml)

##                                                                                                                          book
## title           Fundamentals of Machine Learning for Predictive Data Analytics: Algorithms, Worked Examples, and Case Studies
## author                                                                        John D. Kelleher, Brian Mac Namee, Aoife D'Arcy
## publicationDate                                                                                                    2015-07-04
## publisher                                                                               Massachusetts Institute of Technology
##                                                                                book.1
## title           Machine Learning: Hands-On for Developers and Technical Professionals
## author                                                                     Jason Bell
## publicationDate                                                            2014-11-03
## publisher                                                     John Wiley and Sons Inc
##                                  book.2
## title           Machine Learning with R
## author                      Brett Lantz
## publicationDate              2013-11-25
## publisher              Packt Publishing

#data frame for JSON
print(df4json)

##                                                                                                      book.title
## 1 Fundamentals of Machine Learning for Predictive Data Analytics: Algorithms, Worked Examples, and Case Studies
## 2                                         Machine Learning: Hands-On for Developers and Technical Professionals
## 3                                                                                       Machine Learning with R
##                                       book.author            book.date
## 1 John D. Kelleher, Brian Mac Namee, Aoife D'Arcy 2015-07-24T00:00:00Z
## 2                                      Jason Bell 2014-11-03T00:00:00Z
## 3                                     Brett Lantz 2013-10-25T00:00:00Z
##                          book.publisher
## 1 Massachusetts Institute of Technology
## 2               John Wiley and Sons Inc
## 3                      Packt Publishing

Conclusion

All the data frames contain the informations displayed in the initial files. It is showing that the data frames for HTML and JSON have the same structure. In those datafiles, the informations about the books are mixed together. The data frame for XML is different, it follows the input file structure.