Why Ruby prefers iterators over loops - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to iterate over the array using an iterator.

Ruby

numbers = [1, 2, 3, 4]
numbers.[1] do |num|
  puts num
end

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

Aeach

Bfor

Cwhile

Dloop

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'for' which is a loop keyword, not an iterator method.

Using 'while' which is a loop structure, not a method on arrays.

Ruby prefers each as an iterator to loop over collections because it is more readable and expressive.

2fill in blank

medium

Complete the code to sum all elements using an iterator.

Ruby

numbers = [1, 2, 3, 4]
sum = 0
numbers.[1] do |num|
  sum += num
end
puts sum

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

Auntil

Bfor

Ceach

Dwhile

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'for' which is a loop, not an iterator method.

Using 'while' or 'until' which are loop keywords, not methods.

The each method iterates over each element, allowing us to sum them easily.

3fill in blank

hard

Fix the error in the iterator method name.

Ruby

fruits = ['apple', 'banana', 'cherry']
fruits.[1] do |fruit|
  puts fruit.capitalize
end

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

Aeach

Beachh

Cfor

Dloop

Attempts:

3 left

💡 Hint

Common Mistakes

Typing 'eachh' with an extra 'h'.

Using 'for' which is a loop keyword, not a method.

The correct iterator method is each. Misspelling it causes a method error.

4fill in blank

hard

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

Ruby

words = ['cat', 'house', 'dog', 'elephant']
lengths = words.inject({}) { |acc, word|
  if word.length [1] 3
    acc.merge({word=> word.length})
  end
  acc
}

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

A:

B>

C<

D=>

Attempts:

3 left

💡 Hint

Common Mistakes

Using ':' instead of '=>', which is Python syntax.

Using '<' instead of '>' in the condition.

In Ruby, hashes use => to map keys to values. The condition checks if word length is greater than 3.

5fill in blank

hard

Fill both blanks to select even numbers and square them in a hash.

Ruby

numbers = [1, 2, 3, 4, 5]
even_squares = numbers.inject({}) { |acc, num|
  if num % 2 [2] 0
    acc.merge({num=> num[1] 2})
  end
  acc
}

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

A=>

B**

C==

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using ':' instead of '=>' for hashes.

Using '+' instead of '**' for squaring.

Using '=' instead of '==' for comparison.

Use => to map keys to values in the hash, ** to square numbers, and == to check equality.