Ruby.new

Ruby.new
INTRODUCTION TO RUBY
Thursday, February 28, 13

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jakefolio
http://jakefolio.com
[email protected]
Jake Smith

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http://bit.ly/YKoi0z
Links and Resources

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History
1

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http://www.flickr.com/photos/rrrodrigo/2393323487/
Yukihiro Matsumoto
SmallTalk
Perl
LISP
Python
Created Ruby in 1995 in Japan.
The ﬁrst english speaking user
group was not created until Ruby
1.3 (1999)

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Ruby
2

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Everything is
an Object

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Everything....
"Hello World".class
# => String
5.class
# => Fixnum
5000000000000000000.class
# => Bignum
3.14.class
# => Float
nil.class
# => NilClass
true.class
# => TrueClass
false.class
# => FalseClass WAT?

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Variables
foo_bar
# => Local Variable
Foobar
# => Constant
@foo_bar
# => Instance Variable
@@foo_bar
# => Class Variable
$foo_bar
# => Global Variable

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Conventions

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current_user = User.find(1)
random_ids = [2,6,4,6,36,67,77,5,4]
random_ids.uniq
random_ids
# => [2, 6, 4, 6, 36, 67, 77, 5, 4]
random_ids.uniq!
random_ids
# => [2, 6, 4, 36, 67, 77, 5]
random_ids.include? 4
# => true
Lower case and _ seperated
Modify in place
Expect a boolean response

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Data Types
3

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String
"Grumpy wizards make toxic brew"
# => Grumpy wizards make toxic brew
subject + " make toxic brew"
"#{subject} make toxic brew"
'#{subject} make toxic brew'
# => #{subject} make toxic brew
content = <One morning, when Gregor Samsa woke from troubled dreams,
he found himself transformed in his bed into a horrible vermin.
He lay on his armour-like back, and if he lifted his head a little
END

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String
"Grumpy wizards make toxic brew".length
# => 30
"Grumpy wizards make toxic brew".reverse
# => "werb cixot ekam sdraziw ypmurG"
"Grumpy wizards make toxic brew".upcase
# => "GRUMPY WIZARDS MAKE TOXIC BREW"
"".methods
# => Shows all methods available to String, too many to list ;)

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Number
0xfff
# => 4095
1.0e-05
"%f" % 1.0e-5
# => "0.000010"
5 ** 5
# => 3125
128 / 10
# => 12
Where’s my remainder?
String Formatting

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Number
(128 / 10).to_f
# => 12.0
128.0 / 10
# => 12.8
128.to_f / 10
# => 12.8

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Range
(1..100).each { |v| puts v }
# => 1, 2, 3, 4...97, 98, 99, 100
#
(1...100).each { |v| puts v }
# => 2, 3, 4, 5...96, 97, 98, 99
(1...100).to_a.include? 100
# => false
('a'..'z').each { |v| puts v }
# => a, b, c....x, y, z
('a'..'z').covers?('e')
# => true

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Regex
username = "jsmith92@"
match_username = Regexp.new('/^[a-zA-Z0-9_]+$/')
match_username = /^[a-zA-Z0-9_]+$/
username.match match_username
# => nil
username = "jsmith92"
username.match match_username
# => #
find_date = "The conference is taking place on 2013-02-01"
find_date =~ /\d{4}-\d{1,2}-\d{1,2}/
# => 34

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Regex
content = "Welcome to an intro of PHP. PHP the greatest language
EVAR!"
content.sub('PHP', 'Ruby')
# => "Welcome to an intro of Ruby. PHP the greatest language EVAR!"
content.gsub('PHP', 'Ruby')
# => "Welcome to an intro of Ruby. Ruby the greatest language EVAR!"
content.gsub(/php/i, 'Ruby')
# => "Welcome to an intro of Ruby. Ruby the greatest language EVAR!"

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Symbols
user = { :username => 'jdoe' }
user[:username]
# => "jdoe"
"get".to_sym
# => :get
:username.object_id
# => 458088
user2 = { :username => 'jsmith' }
:username.object_id
# => 458088
It’s a String!
Not Really

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Array
greeting = Array.new
greeting = []
greeting.push 'Hello'
# => ["Hello"]
greeting << 'Confoo'
# => ["Hello", "Confoo"]
greeting.join(' ')
# => "Hello Confoo"
%w(Hello Confoo Attendees)
# => ["Hello", "Confoo", "Attendees"]
["Hello", "Confoo", [1, 2, 3]].flatten
# => ["Hello", "Confoo", 1, 2, 3]
Perl inspired
Alternate Notation

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Hash
user = { :name => 'Jake', :location => [32.7828, 96.8039] }
puts user[:name]
# => Jake
puts user[:random]
# => nil
user = Hash.new 'Oh noes I\'m empty'
puts user
# => {}
user[:username]
# => "Oh noes I'm empty"
user.empty?
# => true

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Hash
New in Ruby 1.9
current_user = {
:first_name => 'Jake',
:last_name => 'Smith',
:username => 'jsmith'
}
current_user = {
first_name: 'Jake',
last_name: 'Smith',
username: 'jsmith'
}
current_user.first
# => [:first_name, "Jake"]
New JSON Inspired Format
Order Maintained

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Conditionals
and Loops
4

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Conditionals
if @post.published? and @post.approved?
# Show the post
else
# DO NOT show post
end
unless @user.access?
# Access Denied
end
if [email protected]?
# Access Denied
end
if format == 'xml'
# Base output on XML
elsif format == 'json'
# Do some JSON Hotness
end
@reservation.save if @location.available?
redirect_to users_path and return unless @user.save
Same Conditional

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Conditionals
if ""
puts "Empty String Works"
end
if 0
puts "Zero Works"
end
if nil
puts "Nil Works"
end
if false
puts "False Works"
end

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Conditionals
case ranking
when 1..3
puts "You're at an elite level"
when 4..10
puts "You made it to the second round!"
else
puts "Better luck next year!"
end

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Iterations
users = [
{ name: 'John', username: 'jdoe' },
{ name: 'Jane', username: 'jadoe' },
{ name: 'Jake', username: 'jsmith' }
]
users.each do |user|
puts user[:name]
end
users.each_with_index do |user, index|
puts "[#{index}] #{user[:name]}"
end
user = "Random User Variable"
for user in users
puts user[:name]
end
puts user
# => {:name=>"Jake", :username=>"jsmith"}
User is still defined?

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Looping
3.times { puts "Hello World" }
# => Hello World
# => Hello World
# => Hello World
bottles = 99
while bottles > 0
# take one down pass it...
puts bottles.to_s + " bottles of beer on the wall"
bottles -= 1
end
until file.eof?
# Work with line content
end

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Blocks, Procs,
and Lambdas
5

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Blocks in the Wild
squared = [1,2,3,4].map do |element|
element ** 2
end
puts squared.join(', ')
# => 1, 4, 9, 16

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class Array
def square!(&block)
self.each_with_index do |value, index|
self[index] = yield(value)
end
self
end
end
my_numbers = [1,2,3,4]
my_numbers.square! do |element|
element ** 2
end
puts my_numbers.join(', ')
# => 1, 4, 9, 16

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Block
Proc
Lambda

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Procs and Lambdas
def test_proc
Proc.new { return "Hey look I'm a Proc" }.call
"Finished Proc Test"
end
def test_lambda
lambda { return "Hey look I'm a Lambda" }.call
"Finished Lambda Test"
end
puts test_proc
# => Hey look I'm a Proc
puts test_lambda
# => Finished Lambda Test
Y U NO FINISH?

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Classes
6

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Creating a class
class Asset
def initialize(path)
@path = path
@dimensions = [32, 20]
end
end
image = Asset.new('/images/hello.jpg')

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Accessors
class Asset
attr_accessor :dimensions
attr_reader :path
@path = path
end
end
puts image.dimensions.join('x')
# => 32x20

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Accessors Gotcha
class User
attr_accessor :name
attr_reader :permissions
def initialize(name, *permissions)
@name, @permissions = name, permissions
end
end
current_user = User.new('jake', 'manage.users', 'manage.assets')]
puts current_user.permissions.join(', ')
# => manage.users, manage.assets
current_user.permissions << 'manage.posts'
puts current_user.permissions.join(', ')
# => manage.users, manage.assets, manage.posts

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Methods
class Asset
attr_accessor :dimensions, :path
@path = path
end
def width
@dimensions[0]
end
def height
@dimensions[1]
end
def square?
width == height
end
end
puts "I'm No Square" unless image.square?

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Public, Protected, Private
class Asset
attr_accessor :dimensions, :path
@path = path
end
def square?
width == height
end
protected
def get_type
# get class type
end
end
image.get_type
# => protected method `get_type' called for #0x007f9ce2085508> (NoMethodError)

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Inheritance
class Image < Asset
def get_mime
"image/jpeg"
end
end
class Video < Asset
def fps
30
end
end
image = Image.new('/images/new.jpg')
puts image.dimensions.join('x')
# => 32x20
puts image.get_mime
# => “image/jpeg”

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Modules
Mixins
7

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Creating Module
module HTML5
def render
asset_type = self.get_type
"HTML GOES HERE"
end
end
module Taggable
def slug
self.title.gsub(' ', '-')
end
end

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Namespacing
module Output
module HTML5
def render
asset_type = self.get_type
"HTML GOES HERE"
end
end
end
class Admin::AlbumsController < ApplicationController
restrict_to_permission :edit_pages, :except => [ :index, :show ]
before_filter :login_required, :only => [ :index, :show ]
def users
::User.findByAlbum(self.id)
end
end Global Namespace

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Applying mixin
module SumMixin
def sum
self.inject(:+)
end
end
[4,3,2,1,5,6].sum
# => undefined method `sum' for [4, 3, 2, 1, 5, 6]:Array
(NoMethodError)
Array.send(:include, SumMixin)
puts [4,3,2,1,5,6].sum
# => 21

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Applying mixin
class Array
def sum
self.inject(:+)
end
end
class Array
include SumMixin
end
puts [4,3,2,1,5,6].sum
# => 21

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Tools/Libs
8

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{
frameworks: ['Rails', 'Sinatra'],
build: 'Rake',
deployment: 'capistrano',
library_management: ['gem', 'bundler']
repl: 'irb',
versioning: ['rvm', 'rbenv']
}

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Questions? Concerns?
Complaints?

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Thanks for Listening
jakefolio
http://jakefolio.com
[email protected]
Please Rate Me!
https://joind.in/7946

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