I am Vysakh. I am a web developer.

In Ruby

puts “Hello world”

Ruby is simply simple

Just like english

Variables

You have - basket A with 10 apples - basket B with 20 apples.

Find the sum and difference

basketa = 10 applesbasketb = 20 apples

sum = basketa + basketb=> 10 + 20 = 30

difference = basketb - basketa=> 20 - 10 = 10

basket_a = 10basket_b = 20

sum = basket_a + basket_bdifference = basket_b - basket_a

In Ruby

It is just like what you wrote in your kindergarden answer sheet

Creator of Ruby - Matz

Running the code

Ruby is executed line by line

So output of a single line/logic can be seen using irb

Opening up irb in the terminal

Instead of executing as a program file. Useful for learning, debugging.

Conditionals

cold_weather = true

if cold_weather puts “Wear something warm”else puts “Don’t wear something”end

Ruby code

Most thing in Ruby is Object

2.odd?()=> false

“Vysakh”.length()=> 6

Brackets are optional in Ruby

2.odd?=> false

“Vysakh”.length=> 6

Exercise 1

a) Get a string and check if it is palindrome.

b) Get a number and print the reverse of it.

Hint: use gets to get the input.

Array/List

In Ruby

shopping = [ “milk”, “cheese”, “olive oil”]

Loops

In Ruby

20.times do puts “I must do my homework”end

Also, there are

- loop- while loop- for loop- step - upto

HAPPYRuby is all about making programmer

Mam, please take each item for me to bill

cart = [“biscuit”, milk”, “shampoo”, “tampons” ]

Mam, please take each item for me to bill

cart = [“biscuit”, milk”, “shampoo”, “tampons” ]

cart.each do |item| puts itemend

Exercise 2 - Create an array of marks you got in your last assessment. - Find if the sum of odd numbers is greater than the sum of even numbers, if it is, you have big odds at passing.- Pass this information or bad luck will follow

HASH

In Rubyslang = { “lol” => “laugh out loud”, “brb” => “Be right back” }

slang[“lol”] => laught out loud

Use symbols instead of stringslang = { :lol => “laugh out loud”, :brb => “Be right back” }

slang[:lol] => laught out loud

Symbols in Ruby

:hand.class=> Symbol

Alternate way to write hashslang = { lol: “laugh out loud”, brb: “Be right back” }

slang[:lol] => laught out loud

Exercise 3

- Create a list of ipl team hashes - with batsmen (3) name as key and their sixes as values.

a) Find the sixes hit by a batsmen of a given name

Functions

In Ruby

def y(x) x**3end

y(3) # => 27y(2) # => 8

Exercise 4

a) Create a method rajini_style. Return his dialogue (your favorite).

b) Create a factorial method that gets a number and returns the factorial

Class

class Sports def initialize(players, name) @no_of_players = players @name = name endendcricket = Sports.new(11, “Cricket”)foot_ball = Sports.new(11, “Football”)

Inheritance

a version manager (RVM or rbenv or other)

Install ruby using

rbenvInstalling Ruby using

Installing and setting Ruby

dhhCreator of Ruby on Rails

Installing Rails

Creating a new rails project

Files generated with “rails new myproject” command

Starting Rails server

Check the browserlocalhost:3000

Understanding Rails

A dress shop

Pantsection?

1st floor kid. 2nd section

1st floorhere is your pant

A Rails server

/about

routes.rb

home controller, about action

A Rails server

home controller, about action

here is your html file

Lets do it in Rails

filename: config/routes.rb

Configure the routes to get /about

The corresponding html

and go to ‘/about’ url

Lets open the browser

available in the section?

When the pant is not

Coming back to the kid and pant story

1st floor

I want this specific design

Godown

Oh kid lemme go to the godown and get

In RailsDatabase

home controller, about action

/posts/1

and have an abstraction(model)

Lets create a table

This will create model, migration files

migration - A ruby file that will create, modify tables

posts table

title column of type string

from the ruby file(migration)

Lets create the tables

Rake, a simple ruby build program with capabilities similar to make

This creates the posts table

table records through Rails model

Lets create, manipulate

Post is a Ruby class that Inherits ActiveRecord

app/models/post.rb

Object Relation Mapping(ORM) layer

Active Record is an

tables map to classes,

rows map to objectsrows map to objectsRows map to objects

Columns map to object attributes

Few operations

Lets use this query inRails controller and give it to the user

Configure the routes file

Open up the browser

Show the title, description in html

app/views/show.html.erb

Now lets check the browser

Now lets do all this in one command -> scaffold

This will generate all filesbased on REST Architecture

Guides and resources

http://tryruby.org

http://www.codecademy.com/en/tracks/ruby

http://ruby.learncodethehardway.org/book/

Ruby

Ruby on Railsrailstutorial.org/book

railsforzombies.org

guides.rubyonrails.org/getting_started

railscasts.com

Local Ruby Community - chennair.b

Mailing list - google groups

Meetups - www.meetup.com/chennai-ruby