readRDS and saveRDS in R Programming - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the saveRDS() function do in R?

saveRDS() saves a single R object to a file in a binary format. This file can later be loaded back into R with readRDS().

beginner

How do you load an R object saved with saveRDS()?

You use the readRDS() function and provide the file path. It returns the saved object, which you can assign to a variable.

intermediate

What is the difference between saveRDS()/readRDS() and save()/load() in R?

saveRDS() and readRDS() work with a single object and do not restore the object name automatically. save() and load() can save/load multiple objects and restore their names in the environment.

beginner

Write a simple example to save a data frame df to a file called data.rds.

saveRDS(df, file = "data.rds")

beginner

How do you assign the object loaded from data.rds to a variable my_data?

my_data <- readRDS("data.rds")

Which function do you use to save a single R object to a file?

A readRDS()

B saveRDS()

C load()

D write.csv()

saveRDS() saves a single R object to a file in binary format.

What does readRDS() return when you load a file?

A The saved R object

B Nothing, it just loads the object into the environment

C A list of all objects in the file

D A character string of the file name

readRDS() returns the saved object, which you can assign to a variable.

Which statement is true about saveRDS() and save()?

A <code>saveRDS()</code> saves one object; <code>save()</code> can save multiple objects

B <code>saveRDS()</code> saves multiple objects; <code>save()</code> saves one object

C Both save multiple objects

D Neither saves objects to files

saveRDS() saves a single object; save() can save many objects at once.

If you use readRDS() to load an object, what must you do to use it?

A Use <code>load()</code> afterwards

B Nothing, it loads automatically

C Call <code>attach()</code> on it

D Assign it to a variable

readRDS() returns the object; you must assign it to a variable to use it.

Which file extension is commonly used for files saved with saveRDS()?

A .txt

B .csv

C .rds

D .rdata

Files saved with saveRDS() usually have the .rds extension.

Explain how you would save an R object and then load it back later using saveRDS() and readRDS().

Think about saving first, then loading and assigning.

Describe the main difference between saveRDS()/readRDS() and save()/load() in R.

Consider how many objects each can save and how they restore names.