Ruby style guide essentials - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the recommended indentation style in Ruby?

Use 2 spaces per indentation level. Avoid tabs to keep code consistent and readable.

beginner

How should method names be formatted in Ruby?

Method names should be written in snake_case, using lowercase letters and underscores to separate words.

intermediate

When should you use single quotes vs double quotes for strings in Ruby?

Use single quotes for simple strings without interpolation or special symbols. Use double quotes when you need string interpolation or special characters like \n.

intermediate

What is the preferred way to write blocks in Ruby?

Use curly braces {} for single-line blocks and do...end for multi-line blocks to improve readability.

beginner

How should you handle trailing whitespace and line length in Ruby code?

Avoid trailing whitespace at the end of lines. Keep lines shorter than 80 characters to maintain readability.

What is the correct indentation size recommended in Ruby style guides?

A 2 spaces

B 4 spaces

C 1 tab

D No indentation

Ruby style guides recommend using 2 spaces for indentation to keep code clean and consistent.

Which naming style is preferred for Ruby method names?

A camelCase

B PascalCase

C snake_case

D kebab-case

Ruby method names should use snake_case with lowercase letters and underscores.

When should you use double quotes for strings in Ruby?

A Always

B Only for single characters

C Never

D When the string contains interpolation or special characters

Double quotes allow string interpolation and special characters like newline \n.

Which block syntax is preferred for multi-line blocks in Ruby?

A do...end

B begin...end

C {}

D if...end

Use do...end for multi-line blocks to improve readability.

What is the recommended maximum line length in Ruby style guides?

A 100 characters

B 80 characters

C 120 characters

D No limit

Keeping lines under 80 characters helps maintain code readability.

Explain the key Ruby style guide rules for indentation, method naming, and string quoting.

Think about how to keep code clean and easy to read.

Describe the preferred Ruby block syntax and line length recommendations.

Consider readability and clarity in your answer.

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