Ruby: Learn Ruby in 1 Hour

By Xah Lee. Date: . Last updated: .

This is a Ruby tutorial. I assume you already know a scripting language. (e.g. Python, JavaScript, etc) This intro is designed to quickly get you started. After reading, you should be able to use standard documentation.

Ruby has a interactive command line. In terminal, type irb

This tutorial is based on Ruby 3. [see Ruby Version Release Dates]

Printing

Strings

Numbers and String Conversion

Everything is a Object; Finding Object's Methods

Variables

True, False

Conditional: if then else

Loop, Iteration

Array (List)

Hash Table

Call Shell Command

Defining a Function

Classes and Objects

Defining a class. Class name should start with a capital letter.

# ruby

# Object example

class Xyz

 # initializer
  def initialize(ii)
    @xx = ii # @xx is a instance variable
  end

 # a method. Return the instance variable @xx
  def mm
    @xx
  end

 # a another method.
  def nn(aa)
    @xx + aa
  end

end

# create a object.
myobj = Xyz.new(3)

# call a method
p myobj.mm # 3

# call another method with argument
p myobj.nn(2) # 5

Instance variable must be accessed by methods only. You must define methods to get instance variable's value, or change it. (this is different from Java or Python.)

Writing a Module

# ruby

# Module name must start with Capital letter
module Xyz

 # 
end

Ruby Tutorial

Print

String

Types

Variable

Boolean

Branching

Loop, Iteration

Data Structure

Function

Misc