Arrays and Hashes

Ruby provides two main collection types: Arrays and Hashes.

In this lesson, you will learn how to create, modify, and access elements in Arrays and Hashes.

Defining an Array

Arrays store multiple values in an ordered list.

numbers = [1, 2, 3, 4, 5]
puts numbers

Accessing Array Elements

You can access elements using their index, starting from 0.

fruits = ['Apple', 'Banana', 'Cherry']
puts fruits[0]  # Apple
puts fruits[-1] # Cherry

Adding Elements to an Array

Use push or << to add elements.

numbers = [1, 2, 3]
numbers << 4  # Adds 4 to the end
puts numbers

Defining a Hash

Hashes store key-value pairs.

person = { 'name' => 'Alice', 'age' => 25 }
puts person

Accessing Hash Values

Use keys to access values in a hash.

person = { 'name' => 'Alice', 'age' => 25 }
puts person['name']  # Alice

Adding New Key-Value Pairs to a Hash

You can add new keys dynamically.

person = { 'name' => 'Alice' }
person['age'] = 25
puts person

Listing Hash Keys

You can get all keys using the keys method.

person = { 'name' => 'Alice', 'age' => 25 }
puts person.keys

Congratulations!

You have learned how to use Arrays and Hashes in Ruby.

Next, you will learn how to iterate over collections using loops and iterators.