Select/filter for filtering in Ruby - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to select even numbers from the array.

Ruby

numbers = [1, 2, 3, 4, 5]
even_numbers = numbers.select { |n| n.[1] }

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

Aeven?

Bodd?

Cnil?

Dzero?

Attempts:

3 left

💡 Hint

Common Mistakes

Using odd? instead of even? selects odd numbers.

Using nil? or zero? causes errors or wrong results.

The select method filters elements for which the block returns true. Using even? selects even numbers.

2fill in blank

medium

Complete the code to filter words longer than 4 characters.

Ruby

words = ['cat', 'elephant', 'dog', 'lion']
long_words = words.select { |word| word.length [1] 4 }

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

A<

B<=

C>

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using <= selects words shorter or equal to 4 characters.

Using == selects words exactly 4 characters long.

The block should return true for words longer than 4 characters, so use >.

3fill in blank

hard

Fix the error in the code to select numbers divisible by 3.

Ruby

numbers = [3, 5, 9, 10]
divisible_by_three = numbers.select { |num| num [1] 3 == 0 }

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

Adiv

B%

Cmod

Dremainder

Attempts:

3 left

💡 Hint

Common Mistakes

Using mod or div causes errors because they are not Ruby operators.

Using remainder is a method but requires different syntax.

The modulo operator % returns the remainder. Checking num % 3 == 0 finds numbers divisible by 3.

4fill in blank

hard

Fill both blanks to create a hash of words and their lengths, filtering words shorter than 5 characters.

Ruby

words = ['apple', 'bat', 'car', 'dog']
lengths = words.select { |word| word.length < 5 }.map { |[1]| [[1], [2]] }.to_h

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

Aword

Bword.length

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping keys and values.

Using incorrect variable names.

The hash keys are words (word) and values are their lengths (word.length), filtering words shorter than 5.

5fill in blank

hard

Fill all three blanks to select words starting with 'a' and convert them to uppercase.

Ruby

words = ['apple', 'banana', 'avocado', 'cherry']
result = words.select { |[1]| [2].start_with?('[3]') }.map(&:upcase)

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

Aword

Ca

Dw

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong block variable names.

Using wrong starting letter.

The block variable is word. We check if word starts with 'a'. Then we convert selected words to uppercase.