Type checking with .class and .is_a? in Ruby - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if the variable is exactly an Integer using .class.

Ruby

num = 10
puts num.class == [1]

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AFixnum

BInteger

CNumber

Dint

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'int' or 'Fixnum' which are not valid class names in modern Ruby.

The .class method returns the exact class of an object. To check if num is an Integer, compare num.class with Integer.

2fill in blank

medium

Complete the code to check if the variable is a kind of Numeric using .is_a?.

Ruby

value = 3.14
puts value.[1](Numeric)

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Akind_of?

Binstance_of?

Cis_a?

Dclass_of?

Attempts:

3 left

💡 Hint

Common Mistakes

Using instance_of? which checks only exact class, not subclasses.

The .is_a? method checks if an object is an instance of a class or its subclass. Here, it checks if value is a kind of Numeric.

3fill in blank

hard

Fix the error in the code to correctly check if 'text' is a String using .class.

Ruby

text = "hello"
if text.class [1] String
  puts "It's a string!"
end

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AString

Bequals

Cis_a?

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using single equals = instead of double equals == for comparison.

The code uses a single equals sign = which is assignment, not comparison. To compare classes, use ==.

4fill in blank

hard

Fill both blanks to create a hash of words and their lengths, including only words longer than 3 characters.

Ruby

words = ["cat", "house", "dog", "elephant"]
lengths = {word: word.[1] for word in words if word.[1] [2] 3}

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Alength

Bsize

C>

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using word.length is valid but not in options; using < instead of >.

Use word.size to get the length of the word. The condition word > 3 is invalid, so use word.size > 3 to filter words longer than 3 characters.

5fill in blank

hard

Fill all three blanks to create a hash with uppercase words as keys and their lengths as values, including only words with length greater than 4.

Ruby

words = ["apple", "bat", "carrot", "dog"]
result = { [1]: [2] for w in words if [2] [3] 4 }

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Aw.upcase

Bw.length

C>

Dw.downcase

Attempts:

3 left

💡 Hint

Common Mistakes

Using w.downcase instead of w.upcase for keys; using < instead of >.

Use w.upcase for keys to get uppercase words, w.length for values to get word length, and > to filter words longer than 4 characters.