The document provides an overview of what the author loves about Ruby, summarizing several key features in 3 sentences or less: Ruby allows for concise and clear code with less ceremony than other languages like Java. It features an expressive syntax, powerful enumerable processing methods, and the ability to pass code blocks to functions as arguments. Ruby treats everything as an object, including primitive types like integers, and includes features like ranges, regular expressions, and metaprogramming capabilities.

2. Software Developer living near Washington, DC, USA

3. Original hometown is New York City

4. 25+ years experience, focusing on Ruby and Java, currently studying Android development

5. Technical Interests: Ruby, Android, Clojure

6. Other Interests: Travel, Music, Study of Massage and Asian and European Languages

7. Obligatory Joke, Part 1 A DBA walks into a bar, steps in front of two tables and says...

10. ...ask me again if I forget.

11. ...ask questions if anything I say is not clear.

12. ...feel free to share your own observations and experiences.

14. Expressive Syntax

15. Powerful Enumerable Processing

16. Code Blocks and Closures

17. Everything’s an Object, even 1 and nil

18. Ranges

19. Regular Expressions

20. JRuby

21. IRB

22. OS Scripting Support

23. Metaprogramming

28. Conciseness and Clarity, Not Ceremony: Multiline Strings """ Dear #{customer_name}, Thank you for your purchase on #{formatAsDate(purchase_date)}. We have billed your credit card for #{formatAsMoney(purchase_amount)}. """

30. stooges = ["Moe", "Larry", "Curly"] # or

31. stooges = %w(Moe Larry Curly)

32. country_codes = { 'Thailand' => 'th', 'Singapore' => 'sg' }

33. ['mango', 'pineapple', 'durian'][-1] # “durian”

34. ['mango', 'pineapple', 'durian'].last # “durian”

35. attr_accessor :id, :name

36. 1_234_567 # 1234567

37. Powerful Enumerable Processing irb(main):001:0> nums = (1..12).to_a => [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12] irb(main):002:0> squares = nums.map { |n| n * n } => [1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144] irb(main):003:0> evens = nums.select { |n| n % 2 == 0 } => [2, 4, 6, 8, 10, 12] irb(main):004:0> odds = nums - evens => [1, 3, 5, 7, 9, 11] irb(main):005:0> sum = nums.inject { |sum,n| sum += n } => 78

39. Inside the function, block_given? Can be called to determine the presence/absence of the block. irb(main):001:0> def foo irb(main):002:1> if block_given? ; yield; else; puts "No block given."; end irb(main):003:1> end irb(main):005:0* foo { puts "I'm passing a block." } I'm passing a block. irb(main):006:0> foo No block given.

41. Automatic Cleanup or State Restoration Using Closures File.open('myfile.txt') do |file| file << 'hi' # do something with the file end # the file is automatically closed Dir.chdir('another/dir') do # do something in that directory end # chdir's back to the original directory

42. Everything’s an Object, Even 1 and nil irb(main):020:0> 1.class => Fixnum irb(main):021:0> [].class => Array irb(main):022:0> {}.class => Hash irb(main):023:0> //.class => Regexp irb(main):024:0> self.class => Object irb(main):025:0> nil.class => NilClass irb(main):001:0> (0..10).class => Range

43. Ranges irb(main):004:0> (0..3).class => Range irb(main):005:0> (0..3).to_a => [0, 1, 2, 3] irb(main):006:0> (0...3).to_a => [0, 1, 2] irb(main):007:0> nums = (0..10).to_a => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10] irb(main):008:0> nums[3..5] => [3, 4, 5]

45. =~ returns an index (or nil if not found).

46. === returns a boolean value representing the presence or absence of a match.

47. Can be used in a case statement, and can simulate multimethods in this way.

48. Regular Expression Literals irb(main):001:0> fruits = %w(apple mango peach pear) => [&quot;apple&quot;, &quot;mango&quot;, &quot;peach&quot;, &quot;pear&quot;] irb(main):002:0> fruits.grep /^p/ => [&quot;peach&quot;, &quot;pear&quot;] irb(main):003:0> p_regex = /^p/; fruits.grep p_regex => [&quot;peach&quot;, &quot;pear&quot;]

49. Regular Expression Presence/Absence Using === irb(main):005:0> /^p/ === 'peach' => true irb(main):006:0> /^p/ === 'mango' => false

50. Regular Expression Position Using =~ irb(main):007:0> 'peach' =~ /c/ => 3 irb(main):008:0> 'mango' =~ /c/ => nil

51. Regular Expressions in Case Statements irb(main):013:0> def test_for_a(word) irb(main):014:1> case word irb(main):015:2> when /^a/ irb(main):016:2> puts &quot;#{word} begins with an 'a'.&quot; irb(main):017:2> else irb(main):018:2* puts &quot;#{word} does *not* begin with an 'a'.&quot; irb(main):019:2> end irb(main):020:1> end irb(main):021:0> irb(main):022:0* test_for_a('mango') mango does *not* begin with an 'a'. irb(main):023:0> test_for_a('apple') apple begins with an 'a'.

53. Leverages existing Java libraries and infrastructure.

54. Can be a better Java than Java (e.g. provides irb interactive shell).

55. Unit testing Java code with JRuby (e.g. with rspec) is more flexible and expressive than testing in JUnit.

56. JRuby can be used to script DB access via JDBC.

57. jruby-complete.jar contains Jruby and gem, irb, rake, rdoc, ri utilities.

61. Enables dramatic simplifications, such as attr_accessor

62. Enables on-the-fly method creation, such as creating accessor methods on elements in a parsed XML file.

63. The metaprogrammer’s t-shirt says: “I write code that writes code for food.”