Ruby style guide essentials - Mini Project: Build & Apply

Ruby Style Guide Essentials

📖 Scenario: You are working on a small Ruby project where clean and readable code is important. Following a style guide helps everyone understand and maintain the code easily.

🎯 Goal: You will write Ruby code following essential style guide rules: using snake_case for variable names, proper indentation, and clear method definitions.

📋 What You'll Learn

Use snake_case for variable and method names

Indent code blocks with 2 spaces

Use meaningful variable names

Define a method with proper syntax

Print output using puts

💡 Why This Matters

🌍 Real World

Writing clean Ruby code helps teams work together and maintain projects easily.

💼 Career

Following style guides is a key skill for Ruby developers in professional environments.

1

Create a variable with snake_case

Create a variable called user_name and assign it the string "Alice".

Ruby

# Create a variable called user_name and assign it "Alice"
# Your code here

Hint

Use lowercase letters and underscores for variable names in Ruby.

2

Define a method with proper indentation

Define a method called greet_user that takes no arguments and prints "Hello, " followed by the user_name variable. Use 2 spaces for indentation inside the method.

Ruby

user_name = "Alice"
# Define method greet_user with 2 spaces indentation
# Your code here

Hint

Indent the puts line with 2 spaces inside the method.

3

Call the method to print greeting

Call the method greet_user to display the greeting message.

Ruby

user_name = "Alice"
def greet_user
  puts "Hello, #{user_name}"
end
# Call greet_user method below
# Your code here

Hint

Simply write the method name followed by parentheses or without to call it.

4

Final output: Greeting message

Run the program and print the output of the greet_user method call.

Ruby

user_name = "Alice"
def greet_user
  puts "Hello, #{user_name}"
end
greet_user
# Print output above

Hint

The program should print Hello, Alice exactly.

Practice

1. According to the Ruby style guide essentials, which naming convention should you use for method names?

easy

A. snake_case

B. CamelCase

C. kebab-case

D. PascalCase

Solution

1. Step 1: Understand method naming conventions

   Ruby style guide recommends using snake_case for method names to improve readability.

2. Step 2: Compare options with style guide

   CamelCase and PascalCase are used for classes and modules, not methods.

3. Final Answer:

   snake_case -> Option A

4. Quick Check:

   Method names use snake_case [OK]

Hint: Methods and variables use snake_case, classes use CamelCase [OK]

Common Mistakes:

• Using CamelCase for method names
• Using kebab-case which is invalid in Ruby
• Confusing class naming with method naming

2. Which of the following is the correct way to indent Ruby code according to the style guide?

easy

A. 2 spaces

B. 4 spaces

C. 1 tab

D. No indentation

Solution

1. Step 1: Recall indentation rules

   The Ruby style guide specifies using 2 spaces for indentation to keep code clean and consistent.

2. Step 2: Evaluate options

   4 spaces and tabs are common in other languages but not recommended in Ruby style guide.

3. Final Answer:

   2 spaces -> Option A

4. Quick Check:

   Indent with 2 spaces [OK]

Hint: Always indent Ruby code with 2 spaces, never tabs [OK]

Common Mistakes:

• Using tabs instead of spaces
• Using 4 spaces like in Python or JavaScript
• No indentation causing unreadable code

3. What will be the output of the following Ruby code?

class MyClass
  def greet
    name = 'Alice'
    puts "Hello, #{name}!"
  end
end

obj = MyClass.new
obj.greet

medium

A. SyntaxError

B. Hello, #{name}!

C. Hello, name!

D. Hello, Alice!

Solution

1. Step 1: Understand string interpolation

   Double quotes allow #{name} to be replaced by the variable's value, which is 'Alice'.

2. Step 2: Trace method call and output

   Calling greet prints "Hello, Alice!" to the console.

3. Final Answer:

   Hello, Alice! -> Option D

4. Quick Check:

   Double quotes enable interpolation = Hello, Alice! [OK]

Hint: Double quotes allow #{var} interpolation, single quotes do not [OK]

Common Mistakes:

• Using single quotes expecting interpolation
• Confusing variable name with string literal
• Expecting syntax error from interpolation

4. Identify the style error in the following Ruby code snippet:

class my_class
  def say_hello
    puts 'Hello world'
  end
end

medium

A. Class name should be snake_case

B. Method name should be CamelCase

C. Class name should be CamelCase

D. String should use double quotes

Solution

1. Step 1: Check class naming conventions

   Ruby style guide requires class names to use CamelCase, not snake_case.

2. Step 2: Verify method and string style

   Method name is correctly snake_case; single quotes are allowed if no interpolation needed.

3. Final Answer:

   Class name should be CamelCase -> Option C

4. Quick Check:

   Classes use CamelCase [OK]

Hint: Classes and modules use CamelCase, not snake_case [OK]

Common Mistakes:

• Using snake_case for class names
• Changing method names to CamelCase incorrectly
• Forcing double quotes when not needed

5. You want to define a Ruby method that returns a greeting with a name variable. Which style is best according to the Ruby style guide essentials?

def greetUser(name)
  return 'Hello, ' + name + '!'
end

hard

A. def greetUser(name)
"Hello, #{name}!"
end

B. def greet_user(name)
"Hello, #{name}!"
end

C. def greet_user(name)
'Hello, ' + name + '!'
end

D. def greetUser(name)
'Hello, ' + name + '!'
end

Solution

1. Step 1: Apply method naming conventions

   Method names should use snake_case, so greet_user is correct.

2. Step 2: Use string interpolation with double quotes

   Double quotes allow cleaner string interpolation instead of concatenation.

3. Final Answer:

   def greet_user(name) "Hello, #{name}!" end -> Option B

4. Quick Check:

   snake_case + interpolation = def greet_user(name) "Hello, #{name}!" end [OK]

Hint: Use snake_case for methods and double quotes for interpolation [OK]

Common Mistakes:

• Using CamelCase for method names
• Using single quotes with interpolation expecting it to work
• Concatenating strings instead of interpolation