arulalan ruby an intro
DESCRIPTION
Ruby an introduction. It is 100% OOP Language. And it is very beautiful language.I Love Ruby Very Much. I hope "YOU" tooTRANSCRIPT
Ruby is a Programming Language
There are so many
Programming Languages.
Why Ruby?
Ruby is simple and beautiful
Ruby is Easy to Learn
Ruby is Free Open Source Software
Ruby on Rails – Web Framework
RAA● Ruby Application Archive● 1648 projects
● http://raa.ruby-lang.org
Rubyforge● 5070 projects and libraries
● http://rubyforge.org/
Can do● Text Handling● System Administration● GUI programming● Web Applications● Database Apps● Scientific Applications
● Games● NLP
● ...
History
RubyYukihiro “Matz” Matsumoto
JapanFebruary 24, 1993
Perl Java Python Ruby PHP1987 1991 1993 1995
What is Ruby?
Ruby is…
A dynamic, open source programming language with a focus on simplicity and productivity. It has an elegant syntax that is natural to read and easy to write.
Quick and Easy● Intrepreted Scripting Language● Variable declarations are unnecessary● Variables are not typed● syntax is simple and consistent● memory management is automatic
Object Oriented Programming● Everything is an object● classes, methods, inheritance, etc.● singleton methods● "mixin" functionality by module● iterators and closures
Examples!
5.times { print “Ruby! " }
Ruby! Ruby! Ruby! Ruby! Ruby!
5.times { print “Ruby! " }
Everything isan object
100.next
100.next101
“I love Ruby” .reverse.capitalize
“I love Ruby”
.reverse.capitalize
“Ybur evol i”
3.hours.from_now
3.hours.from_now
Thu Jan 19 22:05:00 Eastern Standard Time 2006
Conventions
Variables
colored_index_cards
Class Names
Person
Symbols
:street_name
Instance Variables
@school_name
Constants
Kilograms_Per_Pound
Input
puts “What is Your name?”
name = gets
name = name.chomp
puts "Hello" + name + " .Welcome"
Flow
if ( score >= 5000 ) puts “You win!”elsif ( score <= 0 ) puts “Game over.”else puts “Current score: #{score}”end
puts “PASS” if mark > 35
Loop
count = 05.times docount += 1puts "Count =" + count.to_s
end
Count = 1Count = 2Count = 3Count = 4Count = 5
count = 0while count < 10puts "Count = " +count.to_scount += 1
end
Blocks
1.upto(5) { |x| puts x }
12345
5.downto(1) do |time| print “#{time}... ” puts “!” if time <= 3end
5... 4... 3... !2... !1... !
Array
Arraynumbers = [ "zero", "one", "two", "three", "four" ]
Arraynumbers = [ "zero", "one", "two", "three", "four" ]
>> numbers[0]
=> "zero"
>> numbers[4]
=> "four"
Arraynumbers = [ "zero", "one", "two", "three", "four" ]
>> numbers[3].upcase
=> "THREE"
>> numbers[3].reverse
=> "eerht"
Sort Arrayprimes = [ 11, 5, 7, 2, 13, 3 ]
Sort Arrayprimes = [ 11, 5, 7, 2, 13, 3 ]
primes.sort
Sort Arrayprimes = [ 11, 5, 7, 2, 13, 3 ]
primes.sort
=> [2, 3, 5, 7, 11, 13]
Sort Arraynames = [ "Shrini", "Bala", "Suresh", "Arul"]
Sort Arraynames = [ "Shrini", "Bala", "Suresh", "Arul"]
names.sort
Sort Arraynames = [ "Shrini", "Bala", "Suresh", "Arul"]
names.sort
=>["Arul", "Bala", "Shrini", "Suresh"]
Multi Type Arraynames = [ "Shrini", "Bala", "Suresh", "Arul", 1, 14, 45,
77, 98.3, 3.14 ]
More on Arrays● Reverse● Length● Delete● Join● Find● More than 100 methods
Hashes
menu = { :idly => 2.50, :dosai => 10.00, :coffee => 5.00, :ice_cream => 5.00}
menu[:idly]2.50
Methods
Methods
def say_hello(name) result = “Hello, #{name}!” return resultend
puts say_hello(“world”)
Methods
def say_hello(name) “Hello, #{name}!”end
puts say_hello(“world”)
Class
Classesclass MathWhiz
def say_square(value) puts value * value
end
end
sam = MathWhiz.new
sam.say_square(5)
Inheritance
class Dog < Animal @catagory = “mammal” @legs = 4end
Module
Modules
module Trig PI = 3.141592654 def Trig.sin(x) # .. end def Trig.cos(x) # .. endend
Modules
require "trig"y = Trig.sin(Trig::PI/4)0.707106780551956
Attributes
class PlainOldRubyObject attr_accessor :food, :drinks attr_reader :advice attr_writer :write_onlyend
Scopeclass Poet #public by default def poetry end
protected def family_legacy end
private def hopes_and_dreams endend
THE ENDof code :-)
How to Learn?
irb● interactive ruby● A ruby Shellnce response● learn as you type
Web sites
Web Sites
http://rubylang.org
www.rubylang.org
www.rubyforge.net
http://www.rubyforum.com/
