Regex literal syntax (/pattern/) in Ruby - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Ruby code using regex literal?

Consider the following Ruby code snippet. What will it print?

Ruby

text = "Hello World"
pattern = /World/
puts text.match?(pattern)

A SyntaxError

B false

C nil

D true

💡 Hint

The regex literal /World/ matches the substring 'World' in the text.

The method match? returns true if the regex matches anywhere in the string. Since 'World' is present, it returns true.

❓ Predict Output

intermediate

What does this regex literal match in Ruby?

What will the following Ruby code output?

Ruby

text = "abc123xyz"
pattern = /\d{3}/
match = text.match(pattern)
puts match[0]

A 123

B \d{3}

C abc

D nil

💡 Hint

The regex /\d{3}/ looks for exactly three digits in a row.

The pattern matches '123' in the string, so match[0] returns '123'.

❓ Predict Output

advanced

What is the output of this Ruby regex literal with anchors?

What will this Ruby code print?

Ruby

text = "start middle end"
pattern = /^start.*end$/
puts text.match?(pattern)

A false

B true

C nil

D SyntaxError

💡 Hint

The regex uses ^ and $ anchors to match the whole string from start to end.

The pattern matches the entire string because it starts with 'start' and ends with 'end' with any characters in between.

❓ Predict Output

advanced

What error does this Ruby regex literal cause?

What error will this Ruby code raise?

Ruby

pattern = /unclosed
puts pattern

A SyntaxError

B No error, prints /unclosed/

C RuntimeError

D NameError

💡 Hint

Regex literals must be closed on the same line in Ruby.

The regex literal is not closed properly, causing a SyntaxError.

🧠 Conceptual

expert

How many matches does this Ruby regex literal find?

Given the code below, how many matches will be found?

Ruby

text = "one1 two2 three3 four4"
pattern = /\w+\d/
matches = text.scan(pattern)
puts matches.size

A 1

B 3

C 4

D 0

💡 Hint

The pattern matches a word followed by a digit.

The scan method finds all substrings matching the pattern. Here, 'one1', 'two2', 'three3', and 'four4' all match.