Logical (boolean) type in R Programming - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of logical operations in R

What is the output of the following R code?

R Programming

x <- c(TRUE, FALSE, TRUE)
y <- c(FALSE, FALSE, TRUE)
result <- x & y
print(result)

A [1] TRUE TRUE TRUE

B [1] TRUE FALSE TRUE

C [1] FALSE FALSE TRUE

D [1] FALSE TRUE FALSE

💡 Hint

Remember that '&' is element-wise AND in R.

The '&' operator compares each element of x and y and returns TRUE only if both are TRUE.

Here, the pairs are (TRUE, FALSE), (FALSE, FALSE), (TRUE, TRUE), so the results are FALSE, FALSE, TRUE.

❓ Predict Output

intermediate

Result of logical negation in R

What will be printed by this R code?

R Programming

flag <- c(TRUE, FALSE, FALSE, TRUE)
neg_flag <- !flag
print(neg_flag)

A [1] FALSE FALSE FALSE FALSE

B [1] FALSE TRUE TRUE FALSE

C [1] TRUE FALSE FALSE TRUE

D [1] TRUE TRUE TRUE TRUE

💡 Hint

The '!' operator flips TRUE to FALSE and vice versa.

The '!' operator negates each element in the logical vector.

So TRUE becomes FALSE, and FALSE becomes TRUE.

❓ Predict Output

advanced

Logical vector recycling in R

What is the output of this R code snippet?

R Programming

a <- c(TRUE, FALSE)
b <- c(TRUE, TRUE, FALSE, FALSE)
result <- a | b
print(result)

A [1] TRUE FALSE TRUE FALSE

B [1] TRUE TRUE TRUE TRUE

C [1] TRUE TRUE FALSE FALSE

D [1] TRUE TRUE TRUE FALSE

💡 Hint

Remember R recycles shorter vectors to match the length of longer vectors.

The vector a is recycled to length 4: TRUE, FALSE, TRUE, FALSE.

Then element-wise OR with b gives TRUE, TRUE, TRUE, FALSE.

❓ Predict Output

advanced

Logical indexing with boolean vectors in R

What will this R code print?

R Programming

values <- c(10, 20, 30, 40, 50)
filter <- c(TRUE, FALSE, TRUE, FALSE, TRUE)
selected <- values[filter]
print(selected)

A [1] 10 30 50

B [1] 20 40

C [1] 10 20 30 40 50

D [1] 30 50

💡 Hint

Logical vectors can be used to pick elements from another vector.

The logical vector filter selects elements where it is TRUE.

So elements 1, 3, and 5 from values are selected.

🧠 Conceptual

expert

Understanding the difference between '&' and '&&' in R

Which statement best describes the difference between '&' and '&&' in R?

A '&' performs element-wise logical AND on vectors; '&&' evaluates only the first element of each vector.

B '&' performs logical OR; '&&' performs logical AND.

C '&' and '&&' are interchangeable and produce the same result for all inputs.

D '&' is used only for single logical values; '&&' works on vectors element-wise.

💡 Hint

Think about how R treats vectorized logical operations versus single comparisons.

The single ampersand '&' compares each element of vectors and returns a vector of results.

The double ampersand '&&' only compares the first element of each vector and returns a single TRUE or FALSE.