String methods (upcase, downcase, strip) in Ruby - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Ruby code?

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

Ruby

str = "  Hello World  "
puts str.strip.upcase

A "hello world"

B " HELLO WORLD "

C "HELLO WORLD"

D "Hello World"

💡 Hint

Remember that strip removes spaces at the start and end, and upcase makes all letters uppercase.

The strip method removes spaces at the beginning and end of the string, so " Hello World " becomes "Hello World". Then upcase converts all letters to uppercase, resulting in "HELLO WORLD".

❓ Predict Output

intermediate

What does this Ruby code print?

Look at this code. What is the output?

Ruby

text = "  Ruby Programming  "
puts text.downcase.strip

A "RUBY PROGRAMMING"

B " ruby programming "

C "Ruby Programming"

D "ruby programming"

💡 Hint

Think about what downcase and strip do to the string.

First, downcase converts all letters to lowercase, so " Ruby Programming " becomes " ruby programming ". Then strip removes the spaces at the start and end, leaving "ruby programming".

🔧 Debug

advanced

Why does this code raise an error?

This Ruby code tries to print a string in uppercase after stripping spaces, but it raises an error. What is the cause?

Ruby

str = nil
puts str.strip.upcase

A NoMethodError because <code>nil</code> has no method <code>strip</code>

B SyntaxError because <code>strip</code> is used incorrectly

C TypeError because <code>upcase</code> cannot be called on a string

D No error, it prints an empty string

💡 Hint

Think about what happens if you call a method on nil in Ruby.

The variable str is nil, which means it has no value. Calling strip on nil causes a NoMethodError because nil does not have the strip method.

🧠 Conceptual

advanced

What is the result of chaining these methods?

Given the string " Ruby Rocks! ", what does str.downcase.strip.upcase return?

Ruby

str = "  Ruby Rocks!  "
result = str.downcase.strip.upcase
puts result

A "RUBY ROCKS!"

B "ruby rocks!"

C " RUBY ROCKS! "

D "Ruby Rocks!"

💡 Hint

Remember the order: downcase then strip then upcase.

First, downcase converts all letters to lowercase: " ruby rocks! ". Then strip removes spaces at start and end: "ruby rocks!". Finally, upcase converts all letters to uppercase: "RUBY ROCKS!".

📝 Syntax

expert

Which option causes a syntax error?

Which of these Ruby code snippets will cause a syntax error?

A

str = " hello "
puts str.strip.upcase

B

str = "hello"
puts str.strip.upcase(

C

str = "hello"
puts str.strip.upcase

D

str = " hello "
puts str.strip.downcase

💡 Hint

Look for missing or extra characters in method calls.

Option B has an opening parenthesis after upcase but no closing parenthesis, causing a syntax error.