Capture groups in Ruby - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to capture the word 'cat' from the string.

Ruby

text = "The cat sat on the mat."
match = text.match(/[1]/)
puts match[0]

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

Adog

Bcat

Cmat

Dsat

Attempts:

3 left

💡 Hint

Common Mistakes

Using a word not present in the string.

Forgetting to put the pattern inside slashes.

The regular expression /cat/ matches the substring 'cat' in the text.

2fill in blank

medium

Complete the code to capture the first word using a capture group.

Ruby

text = "Hello world"
match = text.match(/(\w+)[1]/)
puts match[1]

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

A\s

B\d

C\W

D\S

Attempts:

3 left

💡 Hint

Common Mistakes

Using \d which matches digits instead of whitespace.

Using \W which matches non-word characters.

The pattern /(\w+)\s/ captures one or more word characters followed by a whitespace.

3fill in blank

hard

Fix the error in the code to correctly capture the domain from the email.

Ruby

email = "[e-mail]"
domain = email.match(/@(\w+[1]\w+)/)[1]
puts domain

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

A\d

B\s

C\W

D\.

Attempts:

3 left

💡 Hint

Common Mistakes

Not escaping the dot, causing it to match any character.

Using \s which matches whitespace instead of a dot.

The pattern /@(\w+\.\w+)/ captures the domain part after '@', including the dot.

4fill in blank

hard

Fill both blanks to capture the area code and the phone number separately.

Ruby

phone = "[phone]"
match = phone.match(/\(([1])\) ([2])-\d{4}/)
puts match[1]
puts match[2]

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

A\d{3}

B\w+

D\s

Attempts:

3 left

💡 Hint

Common Mistakes

Using \w+ which matches letters and digits, not just digits.

Forgetting to match the space between parts.

The pattern captures three digits inside parentheses as the area code and three digits after the space as the phone number part.

5fill in blank

hard

Fill all three blanks to create a hash with keys as captured words and values as their lengths.

Ruby

text = "red blue green"
result = text.scan(/(\w+) (\w+) (\w+)/).map do |[1], [2], [3]|
  { [1] => [1].length, [2] => [2].length, [3] => [3].length }
end
puts result

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

Aa

Bb

Cc

Dx

Attempts:

3 left

💡 Hint

Common Mistakes

Using the same variable name for all three captures.

Not matching the block parameters with the capture groups.

The block variables a, b, c capture the three words, which are then used as keys with their lengths as values.