Ruby on Rails - Ruby Basics

Introduction

Ruby is a dynamic, open-source programming language with a focus on simplicity and productivity. It has an elegant syntax that is natural to read and easy to write. This guide will introduce you to the basics of the Ruby programming language.

Getting Started with Ruby

To start programming in Ruby, you need to install it on your machine. Follow the instructions on the official Ruby website to install Ruby for your operating system.

Basic Syntax

Ruby has a simple and intuitive syntax. Here are some basic examples:

# Print "Hello, world!" to the console
puts "Hello, world!"

# Define a method
def greet(name)
  "Hello, #{name}!"
end

# Call the method
puts greet("Alice")
                

In this example, puts prints a string to the console, and a method greet is defined and called with the argument "Alice".

Variables and Data Types

Ruby supports several data types, including numbers, strings, arrays, and hashes. Here are some examples:

# Variables and data types
number = 42
name = "Alice"
numbers = [1, 2, 3, 4, 5]
person = { name: "Alice", age: 30 }

# Accessing array elements
puts numbers[0]  # Output: 1

# Accessing hash values
puts person[:name]  # Output: Alice
                

In this example, a number, a string, an array, and a hash are defined and accessed.

Control Structures

Ruby provides several control structures for managing the flow of your program. Here are some examples:

# Conditional statements
age = 18
if age >= 18
  puts "You are an adult."
else
  puts "You are a minor."
end

# Loops
3.times do
  puts "Hello!"
end

numbers.each do |number|
  puts number
end
                

In this example, an if statement is used to check a condition, and loops are used to repeat actions.

Methods

Methods in Ruby are used to encapsulate reusable code. Here are some examples:

# Define a method
def add(a, b)
  a + b
end

# Call the method
puts add(2, 3)  # Output: 5
                

In this example, a method add is defined to add two numbers and is then called with the arguments 2 and 3.

Blocks, Procs, and Lambdas

Ruby supports blocks, Procs, and lambdas for handling chunks of code as objects. Here are some examples:

# Block
[1, 2, 3].each do |number|
  puts number
end

# Proc
my_proc = Proc.new { |name| puts "Hello, #{name}!" }
my_proc.call("Alice")

# Lambda
my_lambda = -> (name) { puts "Hello, #{name}!" }
my_lambda.call("Bob")
                

In this example, a block is used with an array, a Proc is defined and called, and a lambda is defined and called.

Classes and Objects

Ruby is an object-oriented programming language, which means it uses classes and objects to model real-world concepts. Here is an example:

# Define a class
class Person
  attr_accessor :name, :age

  def initialize(name, age)
    @name = name
    @age = age
  end

  def greet
    "Hello, my name is #{@name} and I am #{@age} years old."
  end
end

# Create an object
person = Person.new("Alice", 30)
puts person.greet  # Output: Hello, my name is Alice and I am 30 years old.
                

In this example, a class Person is defined with attributes and methods, and an object is created and used.

Conclusion

This guide introduced the basics of the Ruby programming language, covering basic syntax, variables, control structures, methods, blocks, Procs, lambdas, and object-oriented programming with classes and objects. With these fundamentals, you are ready to start exploring Ruby and building your own applications.