Ruby Programming Language
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This document provides an overview of the Ruby programming language. It discusses Ruby's clean and meaningful syntax, everything being an object, dynamic typing and duck typing, open classes, blocks, mixins, testing, standard library, and gems. Ruby aims to be productive and fun to use.
![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](https://image.slidesharecdn.com/tchelinuxruby-12747048908989-phpapp02/85/Ruby-Programming-Language-4-320.jpg)
![a_variable = 'a b c'.split(' ') #=> ['a','b','c']
a_variable = a_variable.join(' ') #=> 'a b c'
def a_function object_par
puts object_par.crazy_method
end
a_function [1,2,3] #=> error: undefined method 'crazy_method' for class Array
class Array
def crazy_method
return 'crazy method for an array'
end
end
a_function [1,2,3] #=> puts 'crazy method for an array'](https://image.slidesharecdn.com/tchelinuxruby-12747048908989-phpapp02/85/Ruby-Programming-Language-7-320.jpg)
![a_variable = 'a b c'.split(' ') #=> ['a','b','c']
a_variable = a_variable.join(' ') #=> 'a b c'
def a_function object_par
puts object_par.crazy_method
end
a_function [1,2,3] #=> error: undefined method 'crazy_method' for class Array
class Array
def crazy_method
return 'crazy method for an array'
end
end
a_function [1,2,3] #=> puts 'crazy method for an array'](https://image.slidesharecdn.com/tchelinuxruby-12747048908989-phpapp02/85/Ruby-Programming-Language-8-320.jpg)
![[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](https://image.slidesharecdn.com/tchelinuxruby-12747048908989-phpapp02/85/Ruby-Programming-Language-14-320.jpg)
![require 'test/unit'
class TestHtmlParser < Test::Unit::TestCase
must “find all imgs” do
parser = 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']
end
end
class HtmlParser
def initialize html_doc
@content = html_doc
end
def parse_imgs
@content.scan(/imgs+src='(.+?)'/)
end
end](https://image.slidesharecdn.com/tchelinuxruby-12747048908989-phpapp02/85/Ruby-Programming-Language-19-320.jpg)
Ruby Programming Language
- 3. Clean, Elegant and Meaningful Syntax
- 4. 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
- 5. Everything is an Object 10.times { puts “Hello World!” } “Hello World!”.methods
- 6. Dynamic Typing, Duck Typing and Open Classes
- 7. a_variable = 'a b c'.split(' ') #=> ['a','b','c'] a_variable = a_variable.join(' ') #=> 'a b c' def a_function object_par puts object_par.crazy_method end a_function [1,2,3] #=> error: undefined method 'crazy_method' for class Array class Array def crazy_method return 'crazy method for an array' end end a_function [1,2,3] #=> puts 'crazy method for an array'
- 8. a_variable = 'a b c'.split(' ') #=> ['a','b','c'] a_variable = a_variable.join(' ') #=> 'a b c' def a_function object_par puts object_par.crazy_method end a_function [1,2,3] #=> error: undefined method 'crazy_method' for class Array class Array def crazy_method return 'crazy method for an array' end end a_function [1,2,3] #=> puts 'crazy method for an array'
- 9. def a_function object_par puts 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_method return 'this is a crazy feature' end a_function some_obj #=> puts 'this is a crazy_feature'
- 10. def a_function object_par puts 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_method return 'this is a crazy feature' end a_function some_obj #=> puts 'this is a crazy_feature'
- 11. "if it walks like a duck and quacks like a duck, then it is a duck”
- 12. Blocks
- 13. def square an_array return 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: ' + line end end
- 14. [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
- 15. def my_for n n.times { |n| yield(n) } end my_for 3 { |i| puts i } #=> 1 #=> 2 #=> 3
- 16. Mix-in
- 17. class Books < Collection def initialize @books = SomeReader.new('some_file_with_books').get_books end include Enumerable def each @books.each { |book| yield(book) } end end Class Books now have map, select, inject, grep, find_all, include? and more
- 18. Testing
- 19. require 'test/unit' class TestHtmlParser < Test::Unit::TestCase must “find all imgs” do parser = 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'] end end class HtmlParser def initialize html_doc @content = html_doc end def parse_imgs @content.scan(/imgs+src='(.+?)'/) end end
- 20. Standard Library ● erb - .rhtml ● sockets ● threads ● html/xml parser ● ftp, http, imap, pop3, smtp ● tk ● pstore
- 21. And Gems! $ gem install rails $ gem install rspec $ gem search twitter 13,007 gems and counting!
- 22. Productivity and fun And that's it! Duda Dornelles [email protected]