Ruby Startereddie@fju
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current status
80% iOS app, 20% Ruby/Rails
What I want?
Problem Solving
History
まつもと ゆきひろ (Matz)
first released at 1995
2.0 released at 2013
Why Ruby?free, open source, easy to learn
Ruby != Rails
Happy, and Fun
RubiesCRuby(MRI), REE, mRuby, JRuby, IronRuby,Rubinius..etc
Version1.8, 1.9, 2.0
Ruby 1.8 has no future
RVMRuby Version Managerhttps://rvm.io/
EditorsVim, Emacs, TextMate, Sublime Text... etc
git
coding stylehttps://github.com/styleguide/ruby
Variables and Constants
local variablevariable
global variable$variable
instance variable@variable
class variable@@variable
virtual variabletrue, false, self, nil
variable assignmenta = 1x, y, z = 1, 2, 3
Constantbegins with a capital letter, and it can be changed
Reserved word and Keyword
Logic and Flow Control
only false and nil are false
true v.s. TrueClassfalse v.s. FalseClassnil v.s. NilClass
if..elsif..end
unless = if not
if modifier
case .. when..
BEGIN{} and END{}
a = true ? 'a' : 'b'
a ||= 'a'
Comment# single line
Comment=begin .. =end
Loop and Iteration
for.. in..
while .. end
until .. end
until = while not
times
upto, downto
each, each_with_index
Block
Proc
my_square = Proc.new { | x | x ** 2 }my_square.call(10) # 100my_square[10] # 100
lambda, ->
my_lambda = lambda { | x | x ** 2 }# new style in 1.9my_lambda = -> x { x ** 2 }# how to call a lambda?my_lambda.call(10)my_lambda[10]
Proc v.s. lambda
def proc_testputs "hello"my_proc = Proc.new { return 1 }my_proc.callputs "ruby"enddef lambda_testputs "hello"my_lambda = lambda { return 1 }my_lambda.callputs "ruby"end
{} v.s. do..endhttp://blog.eddie.com.tw/2011/06/03/do-end-vs-braces/
Number
Fixnum and Bignum
10 / 3
Stringhttp://ruby-doc.org/core-1.9.2/String.html
single and double quotes
%q v.s. %Q
"%s" % "eddie"
string interpolation
Arrayhttp://ruby-doc.org/core-1.9.2/Array.html
Array.new v.s. []
%w
Hashhttp://ruby-doc.org/core-1.9.2/Hash.html
Hash.new v.s {}
a = { :name => 'eddie' }a = { name: 'eddie' }
Rangehttp://ruby-doc.org/core-1.9.2/Range.html
(1..10) v.s. (1...10)
Methods
def method_name(param)...end
parentheses can be omitted
? and !
return value
Singleton Method
class Catdef walkputs "I'm walking"endendcat = Cat.newdef cat.flyputs "I can fly"endcat.fly
Method Missing
def method_missing(method_name)puts "method: #{method_name} is called!"end[1, 2, 3, 4].hello
Exception Handlingbegin .. rescue.. else.. ensure.. end
def open_my_file(file_name)File.open file_name do |f|puts f.readendendbeginopen_my_file("block_demo.r")rescue => eputs eelseputs "it's working good!"ensureputs "this must be executed, no matter what"end
Object-Oriented Programming
everything in Ruby is an Object
object = state+ behavior
top class = Objecttop class would be BasicObject in Ruby 1.9
class ClassName < ParentClass...end
Naming Convention
initialize
ClassName.new
self = current object
instance and class variable
instance and class method
public, protected and private method
getter and setter
attr_reader, attr_writer andattr_accessor
Open Class
Module
module ModuleName...end
module has no inheritance
module has no instance
require v.s. load
Mixin
Ruby is single inheritance
Duck Typing
include v.s. extend
Gem
gem install PACKAGE_NAME
gem env
Bundle
Gemfile
gem "nokogiri", :git => "git://github.com/tenderlove/nokogiri.git"gem "secret_gem", :path => "~/my_secret_path"
bundle install
pack your own gem!
1. bundle gem NEW_NAME2. gem build NEW_NAME.gemspec3. gem push NEW_NAME.gemhttp://docs.rubygems.org/read/chapter/20
Rake
Ruby Object Model
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