A Little Ruby, A Lot of Objects (Brian Marick)
The goal of this book is to teach you a way to think about computation, to show you how far you can take a simple idea: that all computation consists of sending messages to objects. Prerequisites is reader will know at least one programming language, not necessarily.
Author(s): Brian Marick
NA Pages 
This page covers the following topics related to Ruby : The Fundamentals, Installation, Tweet Fetching, Style, Conventions, and Debugging, Numbers, Strings, Variables, Methods, RubyGems, If and Else, Loops, Collections, Enumerables, File input/output, Reviewing Tweet Fetching, Supplementals, Design and Theory, The Projects.
Author(s): ruby.bastardsbook.com
NA Pages
Ruby is an object-oriented scripting language developed by Yukihiro Matsumoto. Topics covered includes: Installing Ruby, Ruby editors, Notation conventions, Interactive Ruby, Data types, Writing methods, Classes and objects, Exceptions, Syntax - Lexicology, Variables and Constants, Control Structures, Classes, Built-In Functions, Predefined Variables, Predefined Classes, Objects , Array, Class, Comparable, Encoding, Enumerable.
Author(s): Wikipedia .org
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