Ruby
Full course · 21 lessonsRuby is a language of simplicity and productivity, famous for the Rails web framework. It prioritizes developer happiness and elegant code with a philosophy of convention over configuration. These are the definitive free resources — vetted, current, and complete.
Getting Started with Ruby
Install Ruby, run scripts, I/O basics, and understand the interpreter.
Variables and Data Types
Local/instance/class/global variables, dynamic typing, symbols.
Numbers and Arithmetic
Integer/Float semantics, operators, precision, and big numbers.
Strings and String Methods
String manipulation, interpolation, formatting, and mutation.
Control Flow
if/elsif/else, case/when, unless, and loops.
Arrays
Indexing, slicing, sorting, and Enumerable-powered transformation.
Hashes and Symbols
Hash construction, symbol keys, iteration, and transformation.
Methods and Arguments
Method definitions, implicit returns, splat, keyword args, blocks.
Classes and Objects
Class definitions, initialize, attr_*, self, to_s.
Modules and Mixins
include, extend, prepend, and namespace modules.
Inheritance
Subclassing, super, override, and ancestry.
Blocks, Procs, and Lambdas
yield, block params, proc vs lambda semantics, &block.
Enumerable Module
map, select, reduce, group_by, tally, and lazy chains.
Exceptions and Error Handling
begin/rescue/ensure, custom exceptions, raise.
File I/O
File read/write, blocks, iteration, FileUtils.
Regular Expressions
=~, match, scan, gsub, anchors, captures.
Metaprogramming
define_method, method_missing, send, instance_eval.
Gems, Bundler, and Standard Library
Gems, JSON, dates, Net::HTTP, and the standard library.
Testing with Minitest
assertions, test classes, describe/it, mocks.
Threads and Concurrency
Thread.new, Mutex, Queue, Fiber.
Advanced: Pattern Matching and Refinements
Case/in patterns, guards, and refinements.
Free Books
Why's (Poignant) Guide to Ruby
A wildly creative comic-illustrated cult classic that introduces Ruby through storytelling and humor.
Learn Ruby the Hard Way
A classic problem-driven book taking beginners from absolute zero to writing basic Ruby through repetition and explicit exercises.
Ruby Essentials
A concise step-by-step guide covering everything from installation to fundamentals of the Ruby language.
Official Documentation
ruby-lang.org Documentation
The central portal for official language guides, API references, and getting-started resources.
Ruby-Doc.org
The long-standing community-hosted API documentation for core classes and standard libraries.
RubyAPI.org
A blazing-fast modern mobile-friendly interface for browsing Ruby classes, modules, and methods.
Interactive Courses
Video Courses
Practice & Challenges
Exercism — Ruby Track
121 community-sourced exercises with 100% free personal code mentoring from volunteer experts.
Codewars
Solve community-crafted algorithmic challenges filtered by Ruby across hundreds of kata.
HackerRank — Ruby Domain
Practice Ruby-specific challenges from basic control structures to advanced language paradigms.
Reference & Cheatsheets
News & Updates
Community
Reddit r/ruby
The primary community hub for Ruby discussions, troubleshooting, and news.
Ruby Discord
Real-time chat community to connect with fellow Ruby developers and get immediate help.
Ruby-Lang Community Page
The official listing of Ruby community resources including mailing lists, IRC channels, and user groups.