puts “Hello Ruby!”

Clean, Elegant and

Meaningful Syntax

test_string = 'string for test'puts 'matched' if test_string.match 'string'

files = Dir['*.txt']for file in files file_ref = open file file_ref.each_line { |line| puts line.reverse.upcase }end

Everything is an Object

10.times { puts “Hello World!” } “Hello World!”.methods

Dynamic Typing, Duck Typing

andOpen Classes

a_variable = 'a b c'.split(' ') #=> ['a','b','c']a_variable = a_variable.join(' ') #=> 'a b c'

def a_function object_parputs object_par.crazy_method

end

a_function [1,2,3] #=> error: undefined method 'crazy_method' for class Array

class Arraydef crazy_method

return 'crazy method for an array'end

end

a_function [1,2,3] #=> puts 'crazy method for an array'

a_variable = 'a b c'.split(' ') #=> ['a','b','c']a_variable = a_variable.join(' ') #=> 'a b c'

def a_function object_parputs object_par.crazy_method

end

a_function [1,2,3] #=> error: undefined method 'crazy_method' for class Array

class Arraydef crazy_method

return 'crazy method for an array'end

end

a_function [1,2,3] #=> puts 'crazy method for an array'

def a_function object_parputs object_par.crazy_method

end

some_obj = SomeClass.new

a_function some_obj #=> error: undefined method 'crazy_method' for class SomeClass

def some_obj.crazy_methodreturn 'this is a crazy feature'

end

a_function some_obj #=> puts 'this is a crazy_feature'

def a_function object_parputs object_par.crazy_method

end

some_obj = SomeClass.new

a_function some_obj #=> error: undefined method 'crazy_method' for class SomeClass

def some_obj.crazy_methodreturn 'this is a crazy feature'

end

a_function some_obj #=> puts 'this is a crazy_feature'

"if it walks like a duck and quacks like a duck, then it is a duck”

Blocks

def square an_arrayreturn an_array.map { |e| e*e }

end

lines_of_a_doc.each_with_index do |line,i|if i.even? then

puts 'even line: #{line}'else

puts 'odd line: ' + lineend

end

[1,2,3,4].select { |e| e.even? } #=> [2,4]

[1,2,3,4].collect { |e| e.even? } #=> [true,false,true,false]

[1,2,3,4].inject(0) { |sum,e| sum += e } #=> 10

def my_for nn.times { |n| yield(n) }

end

my_for 3 { |i| puts i }

#=> 1#=> 2#=> 3

Mix-in

class Books < Collectiondef initialize

@books = SomeReader.new('some_file_with_books').get_booksend

include Enumerable

def each@books.each { |book| yield(book) }

endend

Class Books now havemap, select, inject, grep, find_all, include?

and more

Testing

require 'test/unit'

class TestHtmlParser < Test::Unit::TestCase

must “find all imgs” doparser = HtmlParser.new '<div class='a'> <br/> <img src='img1.jpg'>\n

<p><img src='img2.jpg'></body>'assert_equal parser.parse_imgs, ['img1.jpg','img2.jpg']

endend

class HtmlParser

def initialize html_doc@content = html_doc

end

def parse_imgs@content.scan(/img\s+src=\'(.+?)\'/)

endend

Standard Library

● erb - .rhtml● sockets● threads● html/xml parser● ftp, http, imap, pop3, smtp● tk● pstore

And Gems!

$ gem install rails

$ gem install rspec

$ gem search twitter

13,007 gems and counting!

Productivity and fun

And that's it!

Duda Dornellesdudassdornelles@gmail.com