library(XML)
library(rjson)
library(plyr)

Read from Html File

file_html<- "C:/Users/JGARCIA/Desktop/books.html"
html<- readHTMLTable(file_html)
htmldataframe<- data.frame(html, stringsAsFactors = FALSE)
names(htmldataframe)<- gsub("NULL.", "", names(htmldataframe))
htmldataframe<- rename(htmldataframe, c("QR.Code" = "QR Code"))
## The following `from` values were not present in `x`: QR.Code
print(htmldataframe)
##    ID                            Title
## 1 001 Elements of Statistical Learning
## 2 002      Studies in Ethnomethodology
## 3 003               R for Data Science
##                                             Authors          Subject
## 1 Trevor Hastie, Robert Tibshirani, Jerome Friedman Machine Learning
## 2                                  Harold Garfinkel        Sociology
## 3                                    Hadley Wickham     Data Science
##       Publisher Year
## 1      Springer 2009
## 2 Prentice-Hall 1967
## 3       Oreilly 2016

Read from XML File

file_xml<- "C:/Users/JGARCIA/Desktop/books.xml"
xmldataframe <- xmlToDataFrame(file_xml, stringsAsFactors = FALSE)
print(xmldataframe)
##                              Title
## 1 Elements of Statistical Learning
## 2      Studies in Ethnomethodology
## 3               R for Data Science
##                                             Authors          Subject
## 1 Trevor Hastie, Robert Tibshirani, Jerome Friedman Machine Learning
## 2                                  Harold Garfinkel        Sociology
## 3                                    Hadley Wickham     Data Science
##       Publisher Year
## 1      Springer 2009
## 2 Prentice-Hall 1967
## 3       Oreilly 2016

Read from json file

file_json<- "C:/Users/JGARCIA/Desktop/books.json"
json<- fromJSON(file = file_json)
jsondataframe <- as.data.frame(json, stringsAsFactors = FALSE)
jsondataframe<- rename(jsondataframe, c("QR.Code" = "QR Code"))
## The following `from` values were not present in `x`: QR.Code
print(jsondataframe)
##    ID                            Title
## 1 001 Elements of Statistical Learning
## 2 002      Studies in Ethnomethodology
## 3 003               R for Data Science
##                                             Authors          Subject
## 1 Trevor Hastie, Robert Tibshirani, Jerome Friedman Machine Learning
## 2                                  Harold Garfinkel        Sociology
## 3                                    Hadley Wickham     Data Science
##       Publisher Year
## 1      Springer 2009
## 2 Prentice-Hall 1967
## 3       Oreilly 2016

Conclusion

The three files looks quite identical. The html data frame is the largest sizes followed by the the xml data frame and json data frame is the smallest in size.