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XML stands for eXtensible Markup Language. XML is designed to transport and store data. If you are not familiar with XML, you can first refer to: (#) Reading and writing XML files in R requires installing an extension package. We can install it by entering the following command in the R console: install.packages("XML", repos = "https://mirrors.ustc.edu.cn/CRAN/") To check if the installation was successful: > any(grepl("XML",installed.packages())) TRUE Create a sites.xml file. The XML file should be in the same directory as the test script. The code is as follows: ## Example 1Googlewww.google.com1112Tutorialwww..com2223Taobaowww.taobao.com333 Next, we can use the XML package to load the data from the XML file: ## Example # Load the XML package library("XML") # Set the filename result <- xmlParse(file="sites.xml") # Print the result print(result) To count the amount of XML data: ## Example # Load the XML package library("XML") # Set the filename result <- xmlParse(file="sites.xml") # Extract the root node rootnode <- xmlRoot(result) # Count the data amount rootsize <- xmlSize(rootnode) # Print the result print(rootsize) Executing the above code outputs the following result: 3 To view node data, use for a specific row, and [] for a specific row and column: ## Example # Load the XML package library("XML") # Set the filename result <- xmlParse(file="sites.xml") # Extract the root node rootnode <- xmlRoot(result) # View the 2nd node's data print(rootnode) # View the 1st data item of the 2nd node print(rootnode[][]) # View the 3rd data item of the 2nd node print(rootnode[][]) Executing the above code outputs the following result: $site 2 www. 222 attr(,"class") "XMLInternalNodeList" "XMLNodeList" 2 www. ### Convert XML to a Data List The above code outputs data in XML format. We can use the `xmlToList()` function to convert the file data into a list format, which is easier to read: ## Example # Load the XML package library("XML") # Set the filename result <- xmlParse(file="sites.xml") # Convert to a list xml_data <- xmlToList(result) print(xml_data) print("============================") # Print the data from the first row, second column print(xml_data[][]) Executing the above code outputs the following result: $site $site$id "1" $site$name "Google" $site$url "www.google.com" $site$likes "111" $site $site$id "2" $site$name "" $site$url "www." $site$likes "222" $site $site$id "3" $site$name "Taobao" $site$url "www.taobao.com" $site$likes "333" "============================" "Google" ### Convert XML to a Data Frame XML file data can be converted into a data frame type, which makes it more convenient for us to manipulate the data: ## Example # Load the XML package library("XML") # Convert XML file data to a data frame xmldataframe <- xmlToDataFrame("sites.xml") print(xmldataframe) Executing the above code outputs the following result: id name url likes 1 1 Google www.google.com 1112 2 www. 2223 3 Taobao www.taobao.com 333