Why Enumerable is Ruby's most powerful module - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to include the Enumerable module in the class.

Ruby

class Collection
  include [1]
end

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

AEnumerableClass

BEnumerableModule

CEnumerable

DEnumerableMixin

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong module name like EnumerableModule or EnumerableClass.

Forgetting to include the module.

The Enumerable module is included by writing include Enumerable inside the class.

2fill in blank

medium

Complete the code to define the required method for Enumerable to work.

Ruby

class Collection
  include Enumerable

  def [1]
    @items.each { |item| yield item }
  end
end

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

Aeach

Bloop

Citerate

Deach_item

Attempts:

3 left

💡 Hint

Common Mistakes

Defining a method with a different name like each_item or iterate.

Not yielding items inside the method.

The Enumerable module requires the class to define an each method that yields items.

3fill in blank

hard

Fix the error in the code to use Enumerable's map method correctly.

Ruby

collection = Collection.new
collection.instance_variable_set(:@items, [1, 2, 3])
result = collection.[1] { |x| x * 2 }

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Amap

Bcollect

Ceach

Dfor_each

Attempts:

3 left

💡 Hint

Common Mistakes

Using each which returns the original collection, not a transformed one.

Using a non-existent method like for_each.

The map method is provided by Enumerable and returns a new array with the results of running the block on each element.

4fill in blank

hard

Complete the code to create a hash with word lengths for words longer than 3 characters.

Ruby

words = ['cat', 'house', 'dog', 'elephant']
lengths = words.inject({}) { |hash, word| word.length [1] 3 ? hash.merge(word: word.length) : hash }

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

A:

B>

C<

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong separator like comma instead of colon.

Using wrong comparison operators like < or ==.

In Ruby, using Enumerable's inject to build a hash conditionally, merge word: word.length when word.length > 3.

5fill in blank

hard

Fill all three blanks to filter and transform a collection using Enumerable methods.

Ruby

numbers = [1, 2, 3, 4, 5]
result = numbers.[1] { |n| n [2] 2 == 0 }.[3] { |n| n * 10 }

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

Aselect

B%

Cmap

Dfilter

Attempts:

3 left

💡 Hint

Common Mistakes

Using filter which is not a Ruby Enumerable method.

Using wrong operators instead of modulo.

Using each instead of map for transformation.

select filters elements where the block returns true. The modulo operator % checks for even numbers. Then map transforms each number by multiplying by 10.