Conditional validations in Ruby on Rails - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to validate presence of :email only if :newsletter is true.

Ruby on Rails

validates :email, presence: true, if: [1]

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

A:newsletter == true

Bnewsletter == true

C-> { newsletter }

D:newsletter

Attempts:

3 left

💡 Hint

Common Mistakes

Using a symbol instead of a lambda for the :if option.

Writing a comparison directly without a lambda.

The if option accepts a lambda to conditionally run the validation. Here, -> { newsletter } checks if newsletter is true.

2fill in blank

medium

Complete the code to validate :age numericality only if :adult is true.

Ruby on Rails

validates :age, numericality: true, if: [1]

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

A:adult

B-> { adult }

Cadult == true

D-> adult

Attempts:

3 left

💡 Hint

Common Mistakes

Passing a symbol instead of a lambda.

Using invalid lambda syntax.

The if option needs a lambda that returns true when adult is true. -> { adult } works correctly.

3fill in blank

hard

Fix the error in the validation to run only if :active is true.

Ruby on Rails

validates :username, presence: true, if: [1]

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

Aactive?

Bactive == true

C:active

D-> { active? }

Attempts:

3 left

💡 Hint

Common Mistakes

Passing a symbol without method name.

Using a boolean expression directly without a lambda.

The if option expects a lambda or symbol. Using -> { active? } correctly calls the method to check if the record is active.

4fill in blank

hard

Fill in the blank to validate :phone presence only if :contact_method equals 'phone'.

Ruby on Rails

validates :phone, presence: true, if: [1]

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

A-> { contact_method == 'phone' }

B:contact_method

C-> { contact_method === 'phone' }

Dcontact_method == 'phone'

Attempts:

3 left

💡 Hint

Common Mistakes

Using triple equals (===) which is not typical for string comparison.

Passing a symbol instead of a lambda.

The if option needs a lambda that returns true when contact_method equals 'phone'. The lambda -> { contact_method == 'phone' } works correctly.

5fill in blank

hard

Fill in the blank to validate :password presence only if :user_signed_in is false and :guest_user is true.

Ruby on Rails

validates :password, presence: true, if: [1]

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

A-> { !user_signed_in && guest_user }

B-> { user_signed_in == false && guest_user == true }

C-> { !user_signed_in and guest_user }

D-> { user_signed_in != true && guest_user }

Attempts:

3 left

💡 Hint

Common Mistakes

Using and instead of && which has different precedence.

Writing conditions outside a lambda.

The if option needs a lambda that returns true only when user_signed_in is false and guest_user is true. The lambda -> { !user_signed_in && guest_user } is clear and correct.