Michael Fitzgerald 
Ruby Pocket Reference [PDF ebook] 
Instant Help for Ruby Programmers

Updated for Ruby 2.2, this handy reference offers brief yet clear explanations of Rubys core elementsfrom operators to blocks to documentation creationand highlights the key features you may work with every day. Need to know the correct syntax for a conditional? Forgot the name of that String method? This book is organized to help you find the facts fast.Ruby Pocket Reference, 2nd Edition is ideal for experienced programmers who are new to Ruby. Whether youve come to Ruby because of Rails, or you want to take advantage of this clean, powerful, and expressive language for other applications, this reference will help you easily pinpoint the information you need.Youll find detailed reference material for:Keywords, operators, comments, numbers, and symbols Variables, pre-defined global variables, and regular expressions Conditional statements, method use, classes, and exception handling Methods for the Basic Object, Object, Kernel, String, Array, and Hash classes Time formatting directives New syntax since Ruby 1.9