Variable-length arguments (*args) in Ruby - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does *args mean in a Ruby method definition?

*args allows a method to accept any number of arguments as an array. It collects all extra arguments passed into the method.

beginner

How do you access the individual arguments passed via *args inside the method?

You can treat args as a normal array and access elements by index, loop over it, or use array methods.

beginner

Example: What will this method print?<br>

def greet(*names)
  names.each { |name| puts "Hello, #{name}!" }
end

greet('Alice', 'Bob')

This will print:<br>Hello, Alice!<br>Hello, Bob!

intermediate

Can a method have both regular parameters and *args?

Yes. Regular parameters come first, then *args collects any remaining arguments.

beginner

What happens if you call a method with *args but pass no extra arguments?

The args array will be empty, so the method still works without errors.

What type of object is args inside a method defined with *args?

A Hash

B String

C Array

D Integer

*args collects extra arguments into an array.

Which of these method definitions correctly uses *args?

A def example(*args); end

B def example(args*); end

C def example(*args,); end

D def example(args); end

The correct syntax is def example(*args).

If a method is defined as def sum(*numbers), how do you call it with three numbers?

A sum([1, 2, 3])

B sum(1, 2, 3)

C sum(1; 2; 3)

D sum(1 2 3)

You pass numbers separated by commas: sum(1, 2, 3).

What will args.length return inside a method defined with *args if called with no arguments?

A Error

B nil

C 1

D 0

If no arguments are passed, args is an empty array, so length is 0.

Can *args be used to accept keyword arguments?

A No, <code>*args</code> only collects positional arguments

B Yes, it collects keyword arguments

C Only if combined with <code>**kwargs</code>

D Only if no positional arguments are passed

*args collects only positional arguments. Keyword arguments require **kwargs.

Explain how *args works in Ruby methods and give a simple example.

Think about how to accept many inputs without naming each one.

Describe how you can combine regular parameters and *args in a method definition.

Order matters in method parameters.