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RUBY BY EXAMPLE

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Ruby is... interpreted object oriented dynamic

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Ruby is... productive intuitive popular

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VARIABLES & TYPES

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Before we begin... a.+(b) a.is_valid? a.decrement!

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$counter @@counter @counter counter Global Class Instance Local

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‘hello’ ‘’‘hello’’’ %q{hello} String Herestring Perl-inspired

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a = ‘James’ b = “Hello #{a}” puts b => “Hello James”

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:hello Symbol

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puts <

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[1,2,3] {:a=>1, :b=>2} {a: 1, b: 2} 0..10 Array Hash (1.8) Hash (1.9) Ranges

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METHODS

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def greet(name) “Hello, #{name}” end greet “James”

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def greet(name=“World”) “Hello, #{name}” end greet “James” greet

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CONTROL FLOW

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if rating >= 4 puts "great" elsif rating == 3 puts "alright" else puts "sucks" end

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unless rating == 5 puts “Try harder” end

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puts “Try harder” unless rating == 5 puts “Seriously” if rating == 1

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case rating when 4..5 puts "great" when 3 puts "alright" else puts "sucks" end

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while !le.has_more_lines? puts !le.next_line end puts !le.next_line while !le.has_more_lines?

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until !le.end_of_!le? puts !le.next_line end puts !le.next_line until !le.end_of_!le?

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for i in 0...!le.line_count puts !le.lines[i] end

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BLOCKS

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[1,2,3,4].each do |i| puts i end

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array.each(&block)

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printer = Proc.new do |i| puts i end [1,2,3,4].each &printer

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printer = lambda { |i| puts i }

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def loggerWrapper puts "Executing Method" yield puts "Done Executing" end loggerWrapper { puts "Weeee!" }

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COLLECTIONS

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Array/Enumerable Operations 109 Hash Operations 50

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[1,2,3,4,5].map { |i| i +1} [1,2,3,4,5].reduce { |i, j| i + j } ({a: '1'}).merge({b: '2'})

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CLASSES

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class Person def initialize(name, age) @name,@age = name,age end end person = Person.new("James", 32)

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class Person attr_accessor :name attr_accessor :age ... end p = Person.new("James", 32) puts p.name, p.age

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class Person ... end class Hero < Person attr_accessor :powers end p = Hero.new("James", 32) p.powers = [“Flying”]

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MODULES & MIXINS

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module StrUtils def self.salt(pass, slt) “#{pass}#{salt}” end def salt(slt) StrUtils::salt(@value, slt) end end

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StrUtils::salt("123", "456")

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class Password include Utils def initialize(value) @value = value end end Password.new("test").salt

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TOOLS OF THE TRADE

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irb Interactive shell ruby Ruby interpreter gem Library manager rake Build tool rails Web framework

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RUBY BY EXAMPLE