Objects in R Language: Secrets

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The post is about objects in R Language. In R everything is an object. The commands run in a session can be saved or loaded in a file as history.

Loading Saved Work

Question 1: How can I retrieve (load) the saved work using the history function in R?
Answer: The loadhistory() function will load an “.Rhistory” file.

loadhistory("d:/file_name.Rhistory")

This function will load the file named “file_name.Rhistory” from D: drive.

The other way may be to access the “.Rhistory” file through the file menu. For this click File and then Load History. From the dialog box, browse the folder where you saved the “.Rhistory” file and click open to start working.

Script File in R

Question 2: How do I use a script of commands and functions saved in a text file?
Answer: The script of commands and functions saved in a text file (also called a script file) can be used to write the following command.

source("d:/file_name.txt")

The “file_name.txt” will load from D: drive.

Question 3: How do I get R to echo back the R commands and functions in a script file that I am sourcing into R? That is, the functions that I have written, I want to see these functions are being executed.
Answer: use echo=TRUE argument by using source() function

source("d:/file_name.txt", echo = T)

Question 4: How do I close the help file when working on a Macintosh operating system?
Answer: Typing just q will close the help file and bring you back to the R console.

Objects in R Language: Currently Available Objects

Question 5: How can I see a list of currently available objects in R?
Answer: Use the objects() or ls() functions to see the list of objects currently available

objects()
ls()
Objects in R Language

Remove Objects and Functions

Question 6: How do I remove/delete unwanted objects and functions?
Answer: The rm() function can be used to delete or remove the objects that are not required. The commands below will delete objects named object_name1 & object_name2 and functions named function_name1 & function_name2.

rm(object_name1, object_names2)
rm(function_name1, function_name2)

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Getting Help with R

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Getting help with R is important to learning the language and getting expertise in R.

Question: How one can get help with different commands in the R Language?
Answer: There are many ways to get help with the different commands (functions). There is a built-in help facility which is similar to the man facility in Unix. For beginners to get help, the help() function or the symbol ‘?‘ (question mark only) can be used to get help with different commands.

Help Function in R

Questions: Provide some examples of getting help with different functions used in R.
Answer: To get more information on any specific command (function), for example for getting help with solve( ), lm( ), plot( ), etc., write the following commands at the prompt:

help(solve)
help(lm)
help(plot)

Question: Can one get help for special symbols, and characters in R Language?
Answer: Yes one can get help for special characters. For example;

help("[[")
help("[")
help("^")
help("$")
help("%%")

Question: What help.start() does?
Answer: The help.start( ) will launch a web browser that allows the help pages to be browsed with hyperlinks. It can be a better way to get help with different functions.

help.search Function

Question: There is help.search( ) command. For what purpose it is?
Answer: The help.search() command allows searching for help in various ways. To get what help.search( ) functions do, write this command at the prompt;

help(help.search)

Question: Provide some details about help.search( ) function and also illustrate it by providing some examples.
Answer: The help.search( ) allows for searching the help system for documentation matching a given character string in the (file) name, alias, title, concept, or keyword entries (or any combination thereof), using either fuzzy matching or regular expression matching. Names and titles of the matched help entries are displayed nicely formatted. The examples are:

help.search("linear")
help.search("linear models")
help.search("print")
help.search("cat")
Getting Help with R Language help.search("linear")

? Operator

Question: How ‘?‘ can be used to get help with different functions and objects in R language?
Answer: The ‘?‘ mark can be used to get help with the Windows version of the R Language. For example;

?print
?help
?"[["
?methods
?lm
Getting Help in R: Frequently Asked Questions About R

MCQs in Statistics

MCQs General Knowledge

Save and Load RData Workspace

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In this post, we will learn about Save and Load RData Workspace

How to Save Work in R Language

Question: Can I save my work in R Language?
Answer: R language facilitates saving one’s R work.

Question: How do you save work done in R?
Answer: All of the objects and functions that are created (your R workspace) can be saved in a file “.RData” by using the “save()” function or the “save.image()” function. It is important that when saving R work in a file, remember to include the “.RData” extension.

save(file = "d:/filename.RData")
save.image("d:/filename.RData")

Workspace in R Language

Question: Is there an alternative to save workspace in R?
Answer: Yes! You can also save the workspace using the file menu. For this, click the File menu and then click Save Workspace. You will see the dialog box, browse to the folder where you want to save the file and provide the file name of your own choice.

Save and Load .RData

Question: How one can access the saved work, while work is saved using “save.image()” function?
Answer: The “load()” function can be used to load a .RData file.

load ("d:/filename.RData")

Question: Is there any other alternative to load the workspace in R?
Answer: The .RData file can be accessed through the file menu. To access the file click File and then load workspace. A dialog box will appear, browse to the folder where you saved the .RData file and click open.

Save and Load RData Workspace

Saving Rhistory

Question: How do one can save all the commands that are used in an R session?
Answer: Saving R commands used in an R session means you want to save the history of your R session in an “.Rhistory” file by using the “history()” function. It is important to include the “.Rhistory” extension when saving the file at a different path.

history("d:/filename.Rhistory")

Question: Can commands in the R session be saved through the File menu?
Answer: Yes, the command in the R session be saved through the file menu. For this click File and then save history. A dialog box will appear, browse to the folder where you want to save the file (that will contain R commands in a session) and provide the file name of your own choice.

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