Return values in R Programming - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this R function call?

Consider the following R function and its call. What value does it return?

R Programming

multiply_and_add <- function(x, y) {
  result <- x * y
  return(result + 5)
}
multiply_and_add(3, 4)

A 17

B 7

C 12

D 15

💡 Hint

Remember the function multiplies x and y first, then adds 5 before returning.

The function multiplies 3 and 4 to get 12, then adds 5, so the return value is 17.

❓ Predict Output

intermediate

What does this R function return when called?

Look at this R function and its call. What is the returned value?

R Programming

check_even <- function(num) {
  if (num %% 2 == 0) {
    return(TRUE)
  } else {
    return(FALSE)
  }
}
check_even(7)

A TRUE

B NULL

C 7

D FALSE

💡 Hint

The function returns TRUE if the number is even, otherwise FALSE.

7 is not even, so the function returns FALSE.

❓ Predict Output

advanced

What is the output of this nested return function?

Analyze the following R code. What value does the function return when called with input 5?

R Programming

nested_return <- function(x) {
  inner <- function(y) {
    return(y * 2)
  }
  return(inner(x) + 3)
}
nested_return(5)

A 10

B 13

C 15

D 8

💡 Hint

The inner function doubles the input, then the outer adds 3.

inner(5) returns 10, then adding 3 gives 13.

❓ Predict Output

advanced

What does this function return when no explicit return is used?

What is the output of this R function call?

R Programming

no_return <- function(x) {
  y <- x + 2
  y * 3
}
no_return(4)

A NULL

B 6

C 18

D 12

💡 Hint

In R, the last evaluated expression is returned if no return() is used.

x=4, y=6, last expression y*3 = 18 is returned.

❓ Predict Output

expert

What is the output of this recursive function call?

Consider this recursive R function. What value does factorial(4) return?

R Programming

factorial <- function(n) {
  if (n == 1) {
    return(1)
  } else {
    return(n * factorial(n - 1))
  }
}
factorial(4)

A 24

B 10

C 16

D 1

💡 Hint

Factorial multiplies n by factorial of n-1 until n is 1.

factorial(4) = 4 * 3 * 2 * 1 = 24.