Using if as expression in Rust - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to assign the correct value using if as an expression.

Rust

let number = 5;
let result = if number > 0 [1] "positive" else "non-positive";
println!("{}", result);

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

A{

B==

C>

D;

Attempts:

3 left

💡 Hint

Common Mistakes

Using comparison operators like '==' instead of starting a block.

Ending the line with a semicolon which would make the expression unit type.

The if expression must be followed by a block {} when it has multiple statements or to clearly define the expression. Here, { starts the block.

2fill in blank

medium

Complete the code to assign the correct string based on the value of score using if as an expression.

Rust

let score = 85;
let grade = if score >= 90 [1] "A" else "B";
println!("Grade: {}", grade);

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

A{

B;

C==

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using a semicolon after the condition which ends the expression.

Using comparison operators instead of starting a block.

The if expression must be followed by a block {} to return a value. Here, { starts the block for the true branch.

3fill in blank

hard

Fix the error in the code by completing the if expression correctly.

Rust

let x = 10;
let y = if x < 5 [1] 1 else 2;
println!("{}", y);

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

A==

B;

C{

D:

Attempts:

3 left

💡 Hint

Common Mistakes

Using a semicolon after the condition which ends the expression.

Using comparison operators instead of braces.

The if expression must have a block {} to return a value. Here, { starts the block for the true branch.

4fill in blank

hard

Complete the code to create a dictionary comprehension that uses if as an expression.

Rust

let words = ["apple", "bee", "cat"];
let lengths = words.iter().map(|word| (word, word.len() { 3 {BLANK_2}} "long" else "short")).collect::<Vec<_>>();

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

A>

B<

C{

D;

Attempts:

3 left

💡 Hint

Common Mistakes

Not using curly braces for the if expression.

Using the wrong comparison operator.

The if expression needs a block {} and a comparison operator > to check if the length is greater than 3.

5fill in blank

hard

Fill all three blanks to assign a value using nested if expressions.

Rust

let num = 7;
let description = if num [1] 0 [2] "positive" else if num [3] 0 {"negative"} else {"zero"};

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

A>

B<

C==

D>=

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong comparison operators that do not cover all cases.

Missing braces for the nested if expression.

The first condition checks if num is greater than 0, the else if checks if it is greater or equal to 0, and the last else covers the negative case with less than 0.