chapter_06.md

Chapter 6: Working with Arrays and Hashes

Overview

Arrays and hashes are essential data structures in Ruby used to organize and store data. This chapter explores how to create, access, and manipulate these structures effectively.

Arrays

Arrays in Ruby are ordered, integer-indexed collections of any object. Here's how to create and manipulate an array:

Creating Arrays

numbers = [1, 2, 3, 4, 5]
names = ["Alice", "Bob", "Charlie"]

Accessing Elements

Elements in an array are accessed by their index:

puts numbers[0]  # Outputs 1
puts names[2]    # Outputs Charlie

Adding Elements

You can add elements to arrays using push or the << operator:

numbers.push(6)
names << "David"

Iterating Over Arrays

Use each to iterate over elements:

names.each do |name|
  puts "Hello, #{name}!"
end

Hashes

Hashes in Ruby are collections of key-value pairs. They are similar to dictionaries in other languages.

Creating Hashes

ages = { "Alice" => 30, "Bob" => 25, "Charlie" => 35 }

Accessing Values

Access values in a hash by using their keys:

puts ages["Alice"]  # Outputs 30

Adding Key-Value Pairs

Add new pairs to hashes like this:

ages["David"] = 28

Iterating Over Hashes

Iterate over key-value pairs using each:

ages.each do |name, age|
  puts "#{name} is #{age} years old."
end