Spaceship operator (<=>) in Ruby - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this spaceship operator comparison?

Consider the following Ruby code using the spaceship operator (<=>). What will be printed?

Ruby

puts 5 <=> 10

A 1

B 0

C nil

D -1

💡 Hint

The spaceship operator returns -1 if the left side is less than the right side.

The spaceship operator returns -1 when the left value is smaller than the right value, 0 if equal, and 1 if greater.

❓ Predict Output

intermediate

What does this spaceship operator expression return?

What is the output of this Ruby code snippet?

Ruby

result = 'apple' <=> 'apple'
puts result

A -1

B 0

C 1

D nil

💡 Hint

The spaceship operator returns 0 when both sides are equal.

Since both strings are the same, the operator returns 0.

❓ Predict Output

advanced

What is the output of this spaceship operator with arrays?

What will this Ruby code print?

Ruby

puts [1, 2, 3] <=> [1, 2, 4]

A -1

B 0

C 1

D nil

💡 Hint

The spaceship operator compares arrays element by element.

The first differing element is 3 vs 4, and since 3 < 4, the result is -1.

❓ Predict Output

advanced

What happens when comparing incompatible types with <=>?

What is the output of this Ruby code?

Ruby

puts 10 <=> '10'

A nil

B 1

C -1

D 0

💡 Hint

The spaceship operator returns nil when the two objects are not comparable.

Since an integer and a string cannot be compared, the operator returns nil.

🧠 Conceptual

expert

How does the spaceship operator behave in custom class sorting?

Given a Ruby class with a custom <=> method, what will be the output of sorting an array of its objects? class Box attr_reader :volume def initialize(volume) @volume = volume end def <=>(other) volume <=> other.volume end end boxes = [Box.new(30), Box.new(10), Box.new(20)] sorted_volumes = boxes.sort.map(&:volume) puts sorted_volumes.inspect

A [30, 20, 10]

B Raises an error

C [10, 20, 30]

D [20, 10, 30]

💡 Hint

The spaceship operator defines how objects are compared during sorting.

The custom <=> compares volumes, so sorting orders boxes by volume ascending.