Rescue modifier (inline form) in Ruby - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of rescue modifier with division by zero

What is the output of this Ruby code?

result = 10 / 0 rescue "error"
puts result

Ruby

result = 10 / 0 rescue "error"
puts result

A 0

B Infinity

C error

D ZeroDivisionError

💡 Hint

The rescue modifier catches exceptions and returns the rescue value instead.

The division by zero raises an exception, but the rescue modifier catches it and returns the string "error".

❓ Predict Output

intermediate

Rescue modifier with method call

What will this Ruby code print?

def greet(name)
  "Hello, #{name}!"
end

message = greet(nil) rescue "No greeting"
puts message

Ruby

def greet(name)
  "Hello, #{name}!"
end

message = greet(nil) rescue "No greeting"
puts message

A Hello, nil!

B No greeting

C TypeError

D Hello, !

💡 Hint

Passing nil to string interpolation does not raise an error.

The method returns "Hello, nil!" because #{nil} becomes "nil". No exception occurs, so rescue is not triggered.

❓ Predict Output

advanced

Rescue modifier with multiple expressions

What is the output of this Ruby code?

value = (1 + 2; raise 'fail') rescue 'rescued'
puts value

Ruby

value = (1 + 2; raise 'fail') rescue 'rescued'
puts value

A SyntaxError

B 3

C fail

D rescued

💡 Hint

The raise happens after 1 + 2, triggering rescue.

The expression raises an exception, so the rescue modifier returns 'rescued'.

❓ Predict Output

advanced

Rescue modifier with method returning nil

What will this Ruby code output?

def maybe_fail
  nil
end

result = maybe_fail rescue "error"
puts result.nil?

Ruby

def maybe_fail
  nil
end

result = maybe_fail rescue "error"
puts result.nil?

A true

B false

C error

D NoMethodError

💡 Hint

No exception is raised, so rescue is not triggered.

The method returns nil normally, so result is nil and result.nil? returns true.

❓ Predict Output

expert

Rescue modifier with chained method calls and exception

What is the output of this Ruby code?

class Box
  def initialize(value)
    @value = value
  end
  def unwrap
    @value or raise "Empty"
  end
end

box = Box.new(nil)
result = box.unwrap rescue "rescued"
puts result

Ruby

class Box
  def initialize(value)
    @value = value
  end
  def unwrap
    @value or raise "Empty"
  end
end

box = Box.new(nil)
result = box.unwrap rescue "rescued"
puts result

A NoMethodError

B rescued

C nil

D Empty

💡 Hint

unwrap raises if @value is nil, rescue catches it.

unwrap raises "Empty" because @value is nil, rescue modifier catches and returns "rescued".