Ruby

Summary

Memorize keywords, tips and code snippets for http://www.ruby-lang.org/en/, the scripting language.

Basics

Question	Answer (memorize)
print a string	puts "hi"
run a ruby script (from the command-line)	ruby hi.ruby
string with variable	"hi #{s}"
string with expression	"hi #{1 + 2}"
multi-line string	"foo bar"

Functions and Structures

Question (memorize)	Answer (memorize)
Ruby term for "Map" (or Associative Array)	Hash
if block	if(i == 5) puts "five" end
define a function	def hi(a) puts a end
invoke a function	hi("you")
define a class	class Hi # Functions end
instantiate a class	h = Hi.new()

Lists

Question	Answer (memorize)
create a list	l = ["foo", "bar"]
append to list	l << "third"
iterate through list	l.each{ |i| puts i }
join a list (into one string)	l.join( "," )
access 2nd element (in a list)	l[1]
shorthand for [3, 4, 5]	3..5
double list	l * 2

Classes and Objects

Question (memorize)	Answer (memorize)
Create a class	<pre>class Hello def salute puts "Hello!" end end

Frameworks

Framework (memorize)	Description (memorize)
gems	ruby packages
build tool	Rake
web app framework	Ruby on Rails
lightweight webapp framework	Camping
RMagick	manipulate images (wraps ImageMagick)

Ruby on Rails

Rails is the most popular framework for creating webapps with ruby.

Question (memorize)	Answer (memorize)
principles	- don't repeat yourself - convention over configuration
scaffolding	skeleton code frameworks
database framework	ActiveRecord
Locomotive	Rails installer (for OS X)
templates	.rhtml files (via ERb - Embedded Ruby)

Pages

See also