R - Interview Questions

Dear readers, these R Interview Questions have been designed specially to get you acquainted with the nature of questions you may encounter during your interview for the subject of R programming. As per my experience good interviewers hardly plan to ask any particular question during your interview, normally questions start with some basic concept of the subject and later they continue based on further discussion and what you answer −

What is R Programming?

What are the different data objects in R?

What makes a valid variable name in R?

What is the main difference between an Array and a matrix?

Which data object in R is used to store and process categorical data?

How can you load and use csv file in R?

How do you get the name of the current working directory in R?

What is R Base package?

How R is used in logistic regression?

How do you access the element in the 2nd column and 4th row of a matrix named M?

What is recycling of elements in a vector? Give an example.

What are different ways to call a function in R?

What is lazy function evaluation in R?

How do you install a package in R?

Name a R packages which is used to read XML files.

Can we update and delete any of the elements in a list?

Give the general expression to create a matrix in R.

which function is used to create a boxplot graph in R?

In doing time series analysis, what does frequency = 6 means in the ts() function?

What is reshaping of data in R?

What is the output of runif(4)?

How to get a list of all the packages installed in R ?

What is expected from running the command - strsplit(x,"e")?

Give a R script to extract all the unique words in uppercase from the string - "The quick brown fox jumps over the lazy dog".

Vector v is c(1,2,3,4) and list x is list(5:8), what is the output of v*x[1]?

Vector v is c(1,2,3,4) and list x is list(5:8), what is the output of v*x[[1]]?

What does unlist() do?

Give the R expression to get 26 or less heads from a 51 tosses of a coin using pbinom.

X is the vector c(5,9.2,3,8.51,NA), What is the output of mean(x)?

How do you convert the data in a JSON file to a data frame?

Give a function in R that replaces all missing values of a vector x with the sum of elements of that vector?

What is the use of apply() in R?

Is an array a matrix or a matrix an array?

How to find the help page on missing values?

How do you get the standard deviation for a vector x?

How do you set the path for current working directory in R?

What is the difference between "%%" and "%/%"?

What does col.max(x) do?

Give the command to create a histogram.

How do you remove a vector from the R workspace?

List the data sets available in package "MASS"

List the data sets available in all available packages.

What is the use of the command - install.packages(file.choose(), repos=NULL)?

Give the command to check if the element 15 is present in vector x.

Give the syntax for creating scatterplot matrices.

What is the difference between subset() function and sample() function in R?

How do you check if "m" is a matrix data object in R?

What is the output for the below expression all(NA==NA)?

How to obtain the transpose of a matrix in R?

What is the use of "next" statement in R?