Guard clauses pattern in Ruby - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to return early if the number is negative.

Ruby

def check_number(num)
  return 'Negative number' if [1]
  'Number is positive'
end

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

Anum < 0

Bnum == 0

Cnum > 0

Dnum >= 0

Attempts:

3 left

💡 Hint

Common Mistakes

Using > instead of < causes the guard clause to trigger incorrectly.

Checking for equality to zero does not catch negative numbers.

The guard clause checks if num is less than zero to return early.

2fill in blank

medium

Complete the guard clause to return early if the string is empty.

Ruby

def greet(name)
  return 'No name provided' if [1]
  "Hello, #{name}!"
end

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

Aname.nil?

Bname == ' '

Cname.length > 0

Dname.empty?

Attempts:

3 left

💡 Hint

Common Mistakes

Using nil? misses empty strings that are not nil.

Checking for a space character does not detect empty strings.

The guard clause uses empty? to check if the string has no characters.

3fill in blank

hard

Fix the error in the guard clause to correctly return if the array is nil or empty.

Ruby

def process_list(list)
  return 'No items' if [1]
  list.map(&:upcase)
end

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Alist.nil? || list.length > 0

Blist.empty? && list.nil?

Clist.nil? || list.empty?

Dlist.nil? && list.empty?

Attempts:

3 left

💡 Hint

Common Mistakes

Using && instead of || causes the condition to fail when only one is true.

Checking length > 0 is the opposite of what is needed.

The guard clause uses || to check if list is either nil or empty.

4fill in blank

hard

Fill both blanks to create a guard clause that returns early if the user is not logged in or inactive.

Ruby

def access_page(user)
  return 'Access denied' if [1] || [2]
  'Welcome!'
end

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

A!user.logged_in?

Buser.active?

C!user.active?

Duser.logged_in?

Attempts:

3 left

💡 Hint

Common Mistakes

Using positive checks without negation causes the guard clause to trigger incorrectly.

Mixing up active and logged_in methods.

The guard clause returns if the user is not logged in or not active.

5fill in blank

hard

Fill all three blanks to create a guard clause that returns early if the input is nil, empty, or not a string.

Ruby

def validate_input(input)
  return 'Invalid input' if [1] || [2] || [3]
  'Input is valid'
end

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

Ainput.nil?

Binput.empty?

C!input.is_a?(String)

Dinput.length == 0

Attempts:

3 left

💡 Hint

Common Mistakes

Using input.length == 0 without checking for nil causes errors.

Not checking the type allows invalid inputs to pass.

The guard clause checks if input is nil, empty, or not a string, returning early if any are true.