Awesome Ruby 1

By:

Sameer Rahmani (@lxsameer)

From:

Who am I ?

I ...

  • have about 12 years experience in programming
  • have over thousands of contributes to FOSS world
  • am official GNU project developer
  • am a member of Debian Python team
  • am an expert on:

C/C++ , Python, PHP, Perl, Javascript, Clojure, Lisp, Lua 

www.iranonrails.ir

Iranian Ruby users group

What Can we do with

Ruby?

Desktop Applications

Mobile Applications

  • Ruby Motion (iOS)
  • Rhodes
  • Apache Flex
  • Susanoo
  • And many others

Robotics & Electronics

and more ...

Web Apps

Enything you want

Why Ruby ?

First of all it's FREE

Ruby is designed to make programmers happy.

- Matz

Ruby brings large increase in productivity

With Non traditional programming​ style

Ruby is easy to

Learn

&

Develop

Too many resources to learn Ruby

Huge community. I mean Huuuge

Lots of useful Gems

Documentation

Ruby knowledge is in demand

Beautiful code

RubyOnRails

And other tools like

  • EventMachine
  • Artoo
  • Sinatra
  • Sidekiq
  • Rescue
  • ....

King of

Meta Programming

Every thing is an object

string = String.new

2.times do 
    puts "Hello world"
end 
# Hello world
# Hello world

1.upto(100) { |i| puts i }
# 1
# 2
...
# 100

some_list = [String, "some string", Integer]

Everything is an Object

class Class
  def some_method
    puts "I'm in 'Class' class"
  end
end

class Test
end

Test.some_method
# I'm in 'Class' class

Blocks

people.each do |person|
  if person.sick?
    doctor.visit person
  else 
    person.jumps_around
  end
end 

hello = Proc.new do |string|
  puts "Hello #{string.upcase}"
end

hello.call 'sameer'
# Hello sameer

Open Classes

class String
  def say_hello
    puts "Hello #{self.to_s}"
  end
end

"sameer".say_hello
# Hello sameer

That's enough

Getting Start

Installing Ruby

Solutions

  • Installing Ruby directly
  • Using RVM
  • Using `rbenv`
  • Using `rbch`

Use ruby installer on MS Windows

Installing using `rbenv`

You need `git` and `build-essentials`

$ git clone https://github.com/sstephenson/rbenv.git ~/.rbenv
$ echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc
$ echo 'eval "$(rbenv init -)"' >> ~/.bashrc
$ git clone https://github.com/sstephenson/ruby-build.git \
 ~/.rbenv/plugins/ruby-build

Now let's install ruby 2.1.4 and make it default

$ rbenv install 2.1.4
$ rbenv versions
    system
    2.1.4
$ rbenv global 2.1.4
$ rbenv versions
    system
   *2.1.4

Basic concepts

  • How the ruby program works?
  • How ruby runs programs?
  • How can I try ruby easily?
  • What is `gem`?
  •  What is `bundler`

The fun part

puts 'Hello World'

Objects

  • "Things" in Ruby are Objects
  •  These "things" come in types called Classes

String, Integer, Class, ActiveRecord::Base

Methods

Methods are verbs - Actions and operations on objects (things)

[7] pry(main)> "IranOnRails".reverse
=> "sliaRnOnarI"
[8] pry(main)> 5.even?
=> false
[9] pry(main)>

Methods

  • Sometimes methods take parameters.
  • Parentheses around parameter are optional
[11] pry(main)> "IranOnRails rocks".sub('IranOnRails', 'Karajlug')
=> "Karajlug rocks"
[12] pry(main)> "IranOnRails rocks".sub 'IranOnRails', 'Karajlug'
=> "Karajlug rocks"
[13] pry(main)>

Kernel Methods

Some of the basic methods are available everywhere

gets    # Read a string from terminal (stdin)
puts "Hey guys"  
exit

Variables

  • Name for objects (things)
  • Place to store things we'll want later
name = "Sameer"
nickname = 'lxsameer'
twitter = "@" + nickname 
PI = 3.14

Strings

[14] pry(main)> "Ruby".length
=> 4
[15] pry(main)> "Ruby".upcase
=> "RUBY"
[16] pry(main)> "Ruby".upcase.capitalize
=> "Ruby"
[17] pry(main)> "Ruby" + "onRails"
=> "RubyonRails"
[18] pry(main)> rails = "onRails"
=> "onRails"
[19] pry(main)> "Ruby#{rails}"
=> "RubyonRails"
[20] pry(main)> "Ruby on Rails".split(' ')
=> ["Ruby", "on", "Rails"]
[21] pry(main)>

Arrays

List of objects (things)

[22] pry(main)> langs = ["Ruby", "Python", "Clojure", "Scala", "C"]
=> ["Ruby", "Python", "Clojure", "Scala", "C"]
[23] pry(main)> langs.count
=> 5
[24] pry(main)> langs.sort.join(', ')
=> "C, Clojure, Python, Ruby, Scala"
[25] pry(main)> langs[3]
=> "Scala"
[26] pry(main)> langs[-1]
=> "C"
[27] pry(main)> langs[1..3]
=> ["Python", "Clojure", "Scala"]
[28] pry(main)>

Hashes

Key/Value associations

[28] pry(main)> frameworks = { "Ruby"   => "RubyOnRails",
                               "Python" => "Django" }              
=> {"Ruby"=>"RubyOnRails", "Python"=>"Django"}
[29] pry(main)> frameworks["Ruby"]
=> "RubyOnRails"
[30] pry(main)> frameworks["PHP"]
=> nil
[31] pry(main)> frameworks
=> {"Ruby"=>"RubyOnRails", "Python"=>"Django"}
[32] pry(main)>

Conditionals

def analyze(page)

  fail '"page" is nil' if page.nil?

  if page.even?
    puts 'Page is even'
  else
    puts 'Page is odd'
  end


end

analyze(10)
  • Everything in ruby has a "truth value"
  • Things that are considered false: false, nil

Loops

5.times { puts "Hey" }

1.upto(10).each { |i| puts i }

i = 0 
while i <= 10
    puts i
    i += 1
end

for i in (1..10) 
    puts i
end

(1..10).each do |i|
    puts i
end

["Ruby", "Python", "Lisp"].each do |i|
    puts i
end

Symbols ! 

[57] pry(main)> "Ruby".object_id
=> 70043392889260
[58] pry(main)> "Ruby".object_id
=> 70043393002600
[59] pry(main)> "Ruby".object_id
=> 70043393124120
[60] pry(main)> "Ruby".object_id
=> 70043393245640
[61] pry(main)> "Ruby".object_id
=> 70043393399880
[62] pry(main)> :Ruby.object_id
=> 3904908
[63] pry(main)> :Ruby.object_id
=> 3904908
[64] pry(main)> :Ruby.object_id
=> 3904908
[65] pry(main)> :Ruby.object_id
=> 3904908
[66] pry(main)>

That's it for today

Whaaat ? I want to learn more

  • tryruby.org
  • Online schools (CodeAcademy, CodeSchool)
  • Local courses
  • Also docs and books are always out there

Get help

IranOnRails community ML

IRC channel on freenode:

  • #iranonrails
  • #ruby
  • #rubyonrails

Where to find me

Website:

lxsameer.com

Email:

lxsameer => gnu.org

Twitter:

@lxsameer

 

I'm always available on IRC:

#5hit     #iranonrails

The End

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