Why control flow directs execution in R Programming - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print numbers from 1 to 5 using a for loop.

R Programming

for (i in [1]) {
  print(i)
}

Drag options to blanks, or click blank then click option'

Aseq(5, 1)

Bc(1, 5)

C1:5

Drange(1, 5)

Attempts:

3 left

💡 Hint

Common Mistakes

Using range(1, 5) which is not valid in R.

Using seq(5, 1) which counts backwards.

The expression 1:5 creates a sequence from 1 to 5 in R, which the for loop uses to print numbers 1 through 5.

2fill in blank

medium

Complete the code to check if a number x is positive and print a message.

R Programming

if ([1] > 0) {
  print("Positive")
}

Drag options to blanks, or click blank then click option'

Ax

Bx != 0

Cx < 0

Dx == 0

Attempts:

3 left

💡 Hint

Common Mistakes

Using x == 0 which checks for zero, not positive.

Using x < 0 which checks for negative numbers.

The condition x > 0 checks if x is positive. Here, x is the variable being compared.

3fill in blank

hard

Fix the error in the code to print 'Even' for even numbers.

R Programming

if (x [1] 2 == 0) {
  print("Even")
}

Drag options to blanks, or click blank then click option'

Arem

Bmod

Cdiv

D%%

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'mod' or 'rem' which are not valid operators in R.

Using 'div' which is not an operator in R.

The modulo operator in R is %%, which gives the remainder of division. Using x %% 2 == 0 checks if x is even.

4fill in blank

hard

Fill both blanks to create a vector of squares of numbers greater than 3.

R Programming

squares <- c()
for ([2] in 1:5) {
  if ([2] > 3) {
    squares <- c(squares, [1]^2)
  }
}

Drag options to blanks, or click blank then click option'

Ax

Bi

Cfor

Dy

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names in the two blanks.

Using 'for' which is a keyword, not a variable.

In R, to create a vector of squares for numbers greater than 3, you use a loop variable like i. Both blanks need the same variable name i.

5fill in blank

hard

Fill all three blanks to create a named list of numbers greater than 2 with their squares.

R Programming

result <- list()
for ([3] in 1:5) {
  if ([3] > 2) {
    result[[paste0([1], [3] )]] <- [2]^2
  }
}

Drag options to blanks, or click blank then click option'

Anum

Bi

Dval

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names for the loop variable.

Using invalid names for the list element.

The list is named with num, the loop variable is i, and the expression uses i to compute squares for numbers greater than 2.