Hi I'm Ashik Ajith

ashikajith@gmail.com

Okay..Lets dive into the Topic

Purpose 

• Getting Started with Ruby
   
• Having Fun with Ruby (Hope so...)
   
• Not a Tutorial  :-(

What is Ruby & WHY ?

• Ruby is a Dynamic programming language
   
• Purely OOP Concept
   
• Influenced by Python, Perl, Lisp and Small Talk
   
• Focus on simplicity and productivity
   
• Created by Yukihiro Matsumoto

History of Ruby (walk through)

• Aim to create a OO Scripting Language
   
• A language that is more powerful than Perl, and more object-oriented than Python
   
• Code-named after a gemstone's name (àla Perl)
   
• Released in 1995(v 0.95) - 
   
• Current Version - Ruby (v2.2.3) 

 

Install Ruby

 #For Ubuntu

• https://www.ruby-lang.org/en/documentation/installation/

 #For Mac and Windows Users

• http://railsinstaller.org/en

To Get Started.. ( Add screnshots)

• Try Ruby! (http://tryruby.org/)

• Ruby in Twenty Minutes
  (https://www.ruby-lang.org/en/documentation/quickstart/)

• Ruby from Other Languages

"Programming languages must feel natural to programmers."

- Matz, creator of Ruby

Ruby With Numbers

#irb console

2 + 2        #=> 4

2 + 3.14     #=> 5.14   

2 - 3.14      #=> -1.1400000000000001
        
2 ** 100     #=> 1267650600228229401496703205376

# Instead of ++ and -- we use += and -=

x = 2 

x += 1       #=> 3 

x -= 1       #=> 2

Ruby With Data types

#irb console

x = 4

x.class  #=> Fixnum

x = 3.142857 

x.class #=> Float   

x = (2 ** 100) 

x.class  #=> Bignum

puts "I can inject variables here #{x} "  #=> Use double quotes

Ruby With Arrays

#irb console

list = ['a','b','c','d']

list << 'e' 

list.pop          #=> "e"

list              #=> ["a", "b", "c", "d"]

list.push 4       #=> ["a", "b", "c", "d", "4"]

Ruby With Ranges

#irb console

 # Exclusive Range

numbers = (1...6)

alphabets = ('a' ... 'j')

range_set = ('abc' ... 'abz') #=> ?

  # Inclusive Range

numbers = (1 .. 6)

alphabets = ('a' .. 'j')

Ruby With Hashes

Hash = {key => value}

hash = {1=> 'one', 2=> 'two', 3=>'three'}

hash[1] #=> 'One'

hash[2] #=> 'Two'

another_hash = { 'a' => 1, 'b' => 2, 'c' => 3 }

another_hash.keys    #=> ["a", "b", "c"] 

another_hash.values  #=> [1, 2, 3]

A Hash is a collection of unique keys and values, Similar to arrays but can use any object type

Ruby With Hashes (Contd..)

#Can Have the values as hash instead of String

vehicles = { 'bikes' => {
                          'honda' => ['CB Uniconorn', 'Dream Yuga', 'Activa'],
                          'royal_enfield' => ['Bullet Classic', 'Deset Storm', 
                                                'Thunder bird']
                         },
             'cars' => {
                          'Ford' => ['Ford Figo', 'Ford Classic']
                        }
            }

vehicles['bikes']['royal_enfield'] #=> ['Bullet Classic', 'Deset Storm', 'Thunder bird']

Ruby With Conditions

if condition
 
    #do something
elsif

    #do something else
end
                                    
do_something if condition


unless condition
  #do something
else
  #do something else  
  

Ruby With Conditions

Switch Statement

$age =  5
case $age
when 0 .. 2
    puts "baby"
when 3 .. 6
    puts "little child"
when 7 .. 12
    puts "child"
when 13 .. 18
    puts "youth"
else
    puts "adult"
end

Ruby With Conditions

While

$i = 0
$num = 5

while $i < $num  do
   puts("Inside the loop i = #$i" )
   $i +=1
end

For

for i in 0..5
   puts "Value of local variable is #{i}"
end

Ruby With Iterations

array_or_range.each do |value|
    puts value
end


array_or_range.map{|e| puts e }

3.times do 
    print 'ha'
end