- Learn Ruby_ Introduction to Ruby Cheatsheet _ Codecademy
- Learn Ruby_ Control Flow in Ruby Cheatsheet _ Codecademy
- Learn Ruby_ Looping with Ruby Cheatsheet _ Codecademy
- Learn Ruby_ Arrays and Hashes Cheatsheet _ Codecademy
- Learn Ruby_ Blocks and Sorting Cheatsheet _ Codecademy
- Learn Ruby_ Hashes and Symbols Cheatsheet _ Codecademy
- Learn Ruby_ Refactoring Cheatsheet _ Codecademy
- Learn Ruby_ Blocks, Procs, and Lambdas Cheatsheet _ Codecademy
- Learn Ruby_ Object-Oriented Programming, Part I Cheatsheet _ Codecademy
- Learn Ruby_ Object-Oriented Programming, Part II Cheatsheet _ Codecademy
Thanks to Codecademy for informatively designed material.