While loop in R Programming - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of a simple while loop

What is the output of the following R code?

R Programming

x <- 1
while (x <= 3) {
  print(x)
  x <- x + 1
}

A

[1] 1
[1] 2

B

[1] 1
[1] 2
[1] 3

C

[1] 1
[1] 2
[1] 3
[1] 4

D Error: object 'x' not found

💡 Hint

The loop runs while x is less than or equal to 3, printing x each time and increasing it by 1.

The loop starts with x = 1 and prints it. Then x increases by 1. This repeats until x becomes 4, which breaks the loop. So it prints 1, 2, and 3.

❓ Predict Output

intermediate

While loop with break statement

What will be printed by this R code?

R Programming

i <- 1
while (TRUE) {
  if (i > 4) break
  print(i)
  i <- i + 1
}

A

[1] 1
[1] 2
[1] 3
[1] 4

B

[1] 1
[1] 2
[1] 3
[1] 4
[1] 5

C Error: object 'i' not found

D

[1] 1
[1] 2
[1] 3

💡 Hint

The loop runs forever until the break condition is met when i is greater than 4.

The loop prints i starting at 1 and increases it by 1 each time. When i becomes 5, the break stops the loop. So it prints 1 to 4.

❓ Predict Output

advanced

While loop with nested if and continue logic

What is the output of this R code?

R Programming

x <- 0
while (x < 5) {
  x <- x + 1
  if (x == 3) next
  print(x)
}

A

[1] 1
[1] 2
[1] 4
[1] 5

B

[1] 1
[1] 2
[1] 3
[1] 4
[1] 5

C

[1] 1
[1] 2
[1] 3
[1] 4

D Error: unexpected symbol in "if (x == 3) next"

💡 Hint

The 'next' statement skips the rest of the loop body when x equals 3.

When x is 3, the 'next' skips the print statement, so 3 is not printed. All other values from 1 to 5 except 3 are printed.

🔧 Debug

advanced

Identify the error in the while loop

What error does this R code produce?

R Programming

count <- 1
while (count < 5) {
  print(count)
  count <- count + 1
}

A Infinite loop printing 1 forever

B Error: object 'count' not found

C Error: unexpected symbol in 'count <- count + 1'

D Prints 1, 2, 3, 4 then stops

💡 Hint

Check the indentation and braces for the while loop body.

With braces, both print and increment are inside the loop, so count increases each iteration until it reaches 5, then loop stops.

🧠 Conceptual

expert

Number of iterations in a while loop

How many times will the loop run in this R code?

R Programming

n <- 10
sum <- 0
while (n > 0) {
  sum <- sum + n
  n <- n - 2
}
sum

A 6

B 10

C 5

D Error: object 'sum' not found

💡 Hint

The loop decreases n by 2 each time until n is no longer greater than 0.

Starting at 10, n decreases by 2 each iteration: 10, 8, 6, 4, 2. After 5 iterations, n becomes 0 and loop stops.