This document introduces Ruby programming concepts through code examples. It covers Ruby basics like variables, numbers, strings, symbols, constants, methods, arrays, hashes, classes and modules. It also discusses the Ruby ecosystem including RVM/rbenv, RubyGems, Bundler and Git/GitHub. The document compares Ruby and Ruby on Rails, lists popular editors for Ruby and provides references for further reading.

1. Lets
start coding
with
Ruby

3. I’m
Muntasim Ahmed
Developer @globo
ishkul.com
https://github.com/amuntasim/
https://www.linkedin.com/in/muntasim/

4. Web Developers?

5. #include <stdio.h>
int main(){
printf(“I love C!”) /*seriously!!*/
return 0;
}

6. public class BigBrother{
public static void main(String[] args) {
String msg=“Hello!! Here is your big brother”
System.out.println(msg);
}
}

7. puts “its really simple! ”
class RubyClass
attr_accessor :v1, :v2
end
r = RubyClass.new
r.v1 = “test”
r.v1 => ‘test’
r.v2 => nil

8. Thank you Matz!

9. Ruby Philosophie
“I believe people want to express themselves
when they program. They don’t want to fight
with the language. Programming languages
must feel natural to programmers. I tried to
make people enjoy programming and
concentrate on the fun and creative part of
programming when they use Ruby.”
-- Yukihiro "Matz" Matsumoto, Ruby creator

10. Why Ruby?
• Its simple
• Easy to write/learn
• Truly object oriented
• Emphasize programming speed!
• Less code, fewer bugs
• Open source

11. From where to start?!
Installation
• Just google with install ruby with
rvm/rbenv in <Your OS>
• Should be simple as like Ruby 

12. From where to start?!
IRB = Interactive Ruby
> Irb
Or
tryruby.org

14. Inside Ruby

15. Everything is an object
3.odd? => true
“string”.length => 6
[].empty? => true
“abc”.methods => [..,..,..]

16. Duck Typing
?!

17. It doesn’t mind
• if you don’t like ‘;’ at the end
• even a method without ()
• If you want to express in your way
• and many more..
Happy Programmer 

20. Variables
• Any plain, lowercase word
• a, my_variable and rubyconf2017
• > a => undefined local variable or method `a`
• > a = ‘hello’ => hello
• > a => hello
• > a = 1 => 1 

21. Number
• Integers (Fixnum), Float
• 1, -3002, 2.3, 1233.1e12
• > 1.class => Fixnum
• >1.3.class => Float
• >1.3e12.class => Float
• >1 + 2 => 3
• >1.4+ 4 => 5.4

22. Strings
• Anything surrounded by quotes ‘’ or “”
• ‘RubyConf 2017’, “Muntasim”
• > a = ‘hello’ => hello
• > a => hello
• > a.upcase => HELLO
• > a.upcase.object_id => 2212289940
• > a.object_id => 2212352200
• > a << ‘ world’ => hello world

23. Symbols
• Start with a colon, look like words
• Uses same object reference
• Useful for keys
• :test, :a
• >"test".object_id => 2212252220
• >"test".object_id => 2212236940
• > :test.object_id => 196968
• > :test.object_id => 196968

24. Constants
• variables, starts with a capital
• Foo, Conf_Date
• :test, :a
 Foo = ‘bar’ => bar
 Foo = ‘dum’ =>’dum’ #warning.
 if something == Foo
#do something
end

25. Methods
def hi
puts ‘Hi there!’
end
 hi => Hi there!
def hello(name)
puts “Hello #{name}!”
end
 hello ‘khoka’ => ‘Hi khoka!’

26. Arrays
• A list surrounded by square brackets
• [1,2,4]
• [‘a’, ‘B’, 1] 
 a = [1,3,5,’7’, ‘e’] => [1,3,5,’7’, ‘e’]
 a[2] => 3
 b = [5,6] => [5,6]
 a+b => [1,3,5,’7’, ‘e’, 5,6]
 ….

27. Hashes
• A list surrounded by curly braces
• {:a => 2, b: ‘3’}
 a = {:a => 2, b: ‘3’} => {:a => 2, b: ‘3’}
 a[:a] => 2, a[:b] => ‘3’
 a.keys => [:a, :b]
 ….

28. Classes
class Car
attr_accessor :wheels, :color
end
 c = Car.new => #<Car:0x00000107b09840>
 c2 = Car.new =>#<Car:0x00000107b00a60>
 c.color = ‘white’ => white
 c.color => white
 c2.color => nil

29. class Car
attr_accessor :wheels, :color
def initialize(wheels, color)
self. wheels = wheels
self. color = color
end
def color_and_wheels
“#{color} color with #{wheels} ‘wheels’)”
end
end
 c = Car.new(4, ‘white’) => #<Car0x00000b09840 .....>
 c.color_and_wheels => ‘white color with 4 wheels’

30. Classes (Open to modify)
class Bird
def make_sound
p “ka-ka-ka”
end
def color
p “black”
end
end
b = Bird.new
b.make_sound => ‘ka-ka-ka’
b.color => ‘black’

31. Classes (Open to modify)
class Bird
def make_sound
p “kuhu :D ”
end
def name
p “a name”
end
b = Bird.new
b.make_sound => ‘kuhu :D’
b.color => ‘black’
b.name => ‘a name’
Don’t like the sound? Just open the class and
modify it

32. Module
 Like classes, modules contain methods and
constants but don’t have instances.
 encourage modular design
 Ruby doesn’t support multiple inheritance
but can have that behavior by modules

33. Module
module M
def m1
end
end
module M
class C
end
end
M.new c = M::C.new

34. Module
class Thing < Parent
include MathFunctions
include Taggable
include Persistence
end

35. module Feature
def feature1
p ‘feature1’
end
def feature2
p ‘feature2’
end
end
module Habits
def habit1
p ‘habit1’
end
def habit2
p ‘habit2’
end
end
class Parent
def a1
p ‘a1’
end
end
class Thing < Parent
include Feature
include Habits
end
t = Thing.new
t.a1 => ‘a1’
t.feature1 => ‘feature1’
t.habit2 => ‘habit2’

36. More on Ruby Basics
• http://rubymonk.com/
• http://tryruby.org/
• http://rubykoans.com/
• http://ruby.learncodethehardway.org/
• http://poignant.guide/ (funny!)

37. Ruby eco system
• RVM/rbenv
• RubyGems
• Bundler
• Git/github

38. Ruby vs Ruby on Rails(aka Rails)
• Rails is written in the Ruby
• Rails uses many Ruby gems
• Rails is a framework
• Rails is used to build web apps
rubyonrails.org

39. Editors
• RubyMine
• Sublime Text
• Textmate
• Vim
• Emacs
• Or whatever you like

40. References:
• https://www.ruby-lang.org/en/
• https://dzone.com/refcardz/essential-ruby
• http://www.jasimabasheer.com/posts/meta_i
ntroduction_to_ruby.html
• http://curriculum.railsbridge.org/docs/