Free R Programming Language MCQ Questions and Answers — Questions and Answers

Question 1: What R syntax should I use to output "Hello World"?

"Hello World"
Hello World'
All of the other answers are correct (Correct answer)
print("Hello World")

Correct answer: All of the other answers are correct

In R, simply typing a string literal like `"Hello World"` or `'Hello World'` into the console will cause R to echo its value as output. Additionally, the `print()` function is explicitly designed to display its arguments to the console. Therefore, all listed options are valid ways to output "Hello World" in R.

Question 2: R is a React alias.

TRUE
FALSE (Correct answer)

Correct answer: FALSE

R is a programming language and software environment specifically designed for statistical computing and graphics. React, on the other hand, is a JavaScript library used for building user interfaces. They are entirely different technologies serving distinct purposes and are not related or aliases of each other.

Question 3: In R code, how do you add comments?

// This is a comment
# This is a comment (Correct answer)
/* This is a comment

Correct answer: # This is a comment

In R, the hash symbol `#` is used to denote a comment. Any text following `#` on a line is ignored by the R interpreter, allowing developers to add explanatory notes within their code. This is the standard and only single-line comment syntax in R.

Question 4: You must specify a variable's data type in R.

TRUE
FALSE (Correct answer)

Correct answer: FALSE

R is a dynamically typed language, meaning you do not need to explicitly declare the data type of a variable when you create it. The R interpreter automatically infers the data type based on the value assigned to the variable. For example, assigning `x <- 5` makes `x` an integer, and `y <- "hello"` makes `y` a character string without prior declaration.

Question 5: How do you make the variable x have the number 5 as its value?

x <- 5 (Correct answer)
x : 5
int x = 5

Correct answer: x <- 5

In R, the `<-` operator is the primary and idiomatic way to assign a value to a variable. It assigns the value on its right to the variable on its left. While `=` can also be used for assignment, `<-` is generally preferred and more common in R programming style.

Question 6: Which function is frequently employed to combine elements?

Concat()
Merge()
Paste() (Correct answer)
Join()

Correct answer: Paste()

The `paste()` function in R is widely used to concatenate or combine character strings and other elements into a single string. It can take multiple arguments and joins them together, by default separated by a space, or by a specified `sep` argument. This makes it ideal for constructing dynamic text outputs.

Question 7: How many variables with the same value are assigned in a single line?

var1 <- var2 <- var3 <- "Orange" (Correct answer)
var1, var2, var3 = "Orange"
var1, var2, var3 <-"Orange"

Correct answer: var1 <- var2 <- var3 <- "Orange"

R supports chained assignment using the `<-` operator. In the syntax `var1 <- var2 <- var3 <- "Orange"`, the value "Orange" is first assigned to `var3`. Then, the value of `var3` is assigned to `var2`, and finally, the value of `var2` is assigned to `var1`. This efficiently assigns the same value to multiple variables in a single line.

Free R Programming Language MCQ Questions and Answers

What R syntax should I use to output "Hello World"?