Ruby for Starter

Transcript

1. 1.

   Ruby Starter eddie@fju

2. 2.

   None
3. 3.

   current status

4. 4.

   80% iOS app, 20% Ruby/Rails

5. 5.

   What I want?

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   Problem Solving

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   History

8. 8.

   まつもと ゆきひろ (Matz)

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   first released at 1995

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    2.0 released at 2013

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    None
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    Why Ruby? free, open source, easy to learn

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    Ruby != Rails

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    Happy, and Fun

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    Rubies CRuby(MRI), REE, mRuby, JRuby, IronRuby, Rubinius..etc

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    Version 1.8, 1.9, 2.0

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    Ruby 1.8 has no future

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    RVM Ruby Version Manager https://rvm.io/

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    Editors Vim, Emacs, TextMate, Sublime Text... etc

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    git

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    coding style https://github.com/styleguide/ruby

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    Variables and Constants

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    local variable variable

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    global variable $variable

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    instance variable @variable

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    class variable @@variable

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    virtual variable true, false, self, nil

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    variable assignment a = 1 x, y, z = 1,

    2, 3
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    Constant begins with a capital letter, and it can be

    changed
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    Reserved word and Keyword

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    Logic and Flow Control

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    only false and nil are false

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    true v.s. TrueClass false v.s. FalseClass nil v.s. NilClass

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    if..elsif..end

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    unless = if not

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    if modifier

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    case .. when..

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    BEGIN{} and END{}

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    a = true ? 'a' : 'b'

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    a ||= 'a'

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    Comment # single line

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    Comment =begin .. =end

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    Loop and Iteration

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    for.. in..

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    while .. end

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    until .. end

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    until = while not

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    times

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    upto, downto

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    each, each_with_index

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    Block

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    Proc

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    my_square = Proc.new { | x | x ** 2

    } my_square.call(10) # 100 my_square[10] # 100
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    lambda, ->

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    my_lambda = lambda { | x | x ** 2

    } # new style in 1.9 my_lambda = -> x { x ** 2 } # how to call a lambda? my_lambda.call(10) my_lambda[10]
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    Proc v.s. lambda

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    def proc_test puts "hello" my_proc = Proc.new { return 1

    } my_proc.call puts "ruby" end def lambda_test puts "hello" my_lambda = lambda { return 1 } my_lambda.call puts "ruby" end
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    {} v.s. do..end http://blog.eddie.com.tw/2011/06/03/do-end-vs-braces/

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    Number

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    Fixnum and Bignum

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    10 / 3

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    String http://ruby-doc.org/core-1.9.2/String.html

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    single and double quotes

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    %q v.s. %Q

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    "%s" % "eddie"

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    string interpolation

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    Array http://ruby-doc.org/core-1.9.2/Array.html

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    Array.new v.s. []

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    %w

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    Hash http://ruby-doc.org/core-1.9.2/Hash.html

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    Hash.new v.s {}

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    a = { :name => 'eddie' } a = {

    name: 'eddie' }
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    Range http://ruby-doc.org/core-1.9.2/Range.html

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    (1..10) v.s. (1...10)

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    Methods

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    def method_name(param) ... end

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    parentheses can be omitted

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    ? and !

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    return value

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    Singleton Method

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    class Cat def walk puts "I'm walking" end end cat

    = Cat.new def cat.fly puts "I can fly" end cat.fly
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    Method Missing

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    def method_missing(method_name) puts "method: #{method_name} is called!" end [1, 2,

    3, 4].hello
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    Exception Handling begin .. rescue.. else.. ensure.. end

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    def open_my_file(file_name) File.open file_name do |f| puts f.read end end

    begin open_my_file("block_demo.r") rescue => e puts e else puts "it's working good!" ensure puts "this must be executed, no matter what" end
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    Object-Oriented Programming

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    everything in Ruby is an Object

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    object = state+ behavior

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    top class = Object top class would be BasicObject in

    Ruby 1.9
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    class ClassName < ParentClass ... end

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    Naming Convention

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    initialize

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    ClassName.new

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    self = current object

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    instance and class variable

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    instance and class method

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    public, protected and private method

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    getter and setter

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    attr_reader, attr_writer and attr_accessor

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     Open Class

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     Module

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     module ModuleName ... end

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     module has no inheritance

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     module has no instance

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     Naming Convention

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     require v.s. load

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     Mixin

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     Ruby is single inheritance

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     Duck Typing

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     include v.s. extend

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     Gem

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     gem install PACKAGE_NAME

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     gem env

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     Bundle

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     Gemfile

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     gem "nokogiri", :git => "git://github.com/tenderlove/nokogiri.git" gem "secret_gem", :path => "~/my_secret_path"

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     bundle install

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     pack your own gem!

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     1. bundle gem NEW_NAME 2. gem build NEW_NAME.gemspec 3. gem

     push NEW_NAME.gem http://docs.rubygems.org/read/chapter/20
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     Rake

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     Ruby Object Model