Predicate methods (ending with ?) in Ruby - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if the number is even using a predicate method.

Ruby

number = 4
puts number.[1]

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Apositive?

Bodd?

Ceven?

Dzero?

Attempts:

3 left

💡 Hint

Common Mistakes

Using odd? instead of even?

Forgetting the question mark at the end of the method

The even? method returns true if the number is even.

2fill in blank

medium

Complete the code to check if the string is empty using a predicate method.

Ruby

text = ""
puts text.[1]

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Aempty?

Bblank?

Cnil?

Dzero?

Attempts:

3 left

💡 Hint

Common Mistakes

Using nil? which checks for nil, not empty string

Using blank? which is not a standard Ruby method

The empty? method returns true if the string has no characters.

3fill in blank

hard

Fix the error in the code to check if the array includes the number 5 using a predicate method.

Ruby

numbers = [1, 2, 3, 4, 5]
puts numbers.[1](5)

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Ainclude

Bcontains?

Cincludes?

Dinclude?

Attempts:

3 left

💡 Hint

Common Mistakes

Using include without the question mark

Using non-existent methods like includes? or contains?

The correct predicate method to check if an array contains an element is include?.

4fill in blank

hard

Fill both blanks to create a hash with keys as words and values as booleans indicating if the word starts with 'a'.

Ruby

words = ["apple", "banana", "avocado"]
result = words.map { |word| [word, word.[1]('a') && word.[2]('a')] }.to_h
puts result

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Astart_with?

Binclude?

Attempts:

3 left

💡 Hint

Common Mistakes

Using include? which checks anywhere in the string, not just the start

Mixing different methods in the two blanks

The start_with? method checks if a string begins with the given prefix.

5fill in blank

hard

Fill the blanks to filter an array of strings to only those that end with 'ing' and check if each is lowercase.

Ruby

words = ["running", "Jumping", "walking", "Talk"]
filtered = words.select { |word| word.[1]('ing') }
result = filtered.map { |word| word.[2] == word }
puts result

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Aend_with?

Bdowncase

Cdowncase == word

Ddowncase?

Attempts:

3 left

💡 Hint

Common Mistakes

Using non-existent method downcase?

Not comparing downcase result to the original word

end_with? checks if the string ends with 'ing'. Then word.downcase == word checks if the word is already lowercase.