Stepping to Ruby

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

Lets Say "Hello" to Ruby

puts "Hello World"

#=> "Hello World"

Ruby Strings

puts "Hello World"

#=> "Hello World"

puts 'Hello World'

#=> "Hello World"

' ' #=> To display as plain string 

" " #=> For String manipulation

put "Hello #{ 5 + 3 } World" 

#=> "Hello 7 World"

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