Inline if and unless (modifier form) in Ruby - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of inline if modifier

What will be the output of this Ruby code snippet?

Ruby

message = "Hello"
message += " World" if message.length < 10
puts message

A Hello World

B Hello

C HelloWorld

D Error

💡 Hint

Check the length of the string before the condition.

The condition checks if the length of 'message' is less than 10, which is true (5). So ' World' is added.

❓ Predict Output

intermediate

Using inline unless modifier

What will this Ruby code print?

Ruby

count = 5
count -= 1 unless count > 5
puts count

A 4

B 5

C 6

D Error

💡 Hint

Remember 'unless' runs the code only if the condition is false.

Since count (5) is not greater than 5, the condition is false, so count is decreased by 1.

🔧 Debug

advanced

Identify the error in inline if usage

Which option shows the code that will raise a syntax error?

A puts "Done" if true; puts "Not done"

B puts "Done" if true

C puts "Done" unless false

D puts "Done" if true else puts "Not done"

💡 Hint

Inline if cannot be combined with else in this way.

Option D tries to use 'else' with inline if, which is invalid syntax in Ruby.

🧠 Conceptual

advanced

Effect of inline unless modifier

What is the value of variable 'status' after running this code?

Ruby

status = "active"
status = "inactive" unless status == "inactive"

A "active"

B "inactive"

C nil

D Error

💡 Hint

The 'unless' runs the assignment only if the condition is false.

Since status is "active", which is not "inactive", the assignment runs and status becomes "inactive".

❓ Predict Output

expert

Output with inline if and method call

What will this Ruby code output?

Ruby

def check(num)
  puts "Even" if num.even?
  puts "Odd" unless num.even?
end
check(3)

A Even\nOdd

B Even

C Odd

D Error

💡 Hint

Check what num.even? returns for 3.

3 is odd, so num.even? is false. The first puts is skipped, the second runs printing 'Odd'.