1. ActiveSupport事始め
2012/8/30 yoyogi.rb

2. 自己紹介
curl http://cui-about.me/nysalor

3. 今回どうしよう

4. 今回どうしよう

5. ActiveSupportについて

6. ActiveSupportについて
パクリ
意外と知らないメソッドが多い
復習の意味で

7. ActiveSupport?
https://github.com/rails/rails/tree/master/activesupport
Railsに入っている便利ライブラリ
Railsをインストールすると勝手に入る
Rails抜きでも使える

8. 試してみよう

9. 試してみよう
% gem install activesupport
Fetching: activesupport-3.2.8.gem (100%)
Successfully installed activesupport-3.2.8
1 gem installed

10. ついでにpryも

11. ついでにpryも
% gem install pry
% gem install pry-coolline

12. pry?
http://pryrepl.org/
irbの強化版

13. インストール

14. インストール
% gem install pry
% gem install pry-coolline

15. 起動

16. 起動
% pry
1.9.3 (main):0 >

17. ActiveSupportを読み込む

18. ActiveSupportを読み込む
1.9.3 (main):0 > require 'active_support/all'
=> true
1.9.3 (main):0 >

19. String系

20. pluralize

21. pluralize
1.9.3 (main):0 > 'magazine'.pluralize
=> “magazines”
1.9.3 (main):0 > 'fantasy'.pluralize
=> “fantasies”

22. singularize

23. singularize
1.9.3 (main):0 > 'magazines'.singularize
=> “magazine”
1.9.3 (main):0 > 'fantasies'. singularize
=> “fantasy”

24. camelize,under_score

25. camelize,under_score
1.9.3 (main):0 > 'active_support'.camelize
=> “ActiveSupport”
1.9.3 (main):0 > 'ActiveSupport'.underscore
=> “active_support”

26. constantize

27. constantize
1.9.3 (main):0 > 'CurrentUser'.constantize
=> CurrentUser

28. from

29. from
1.9.3 (main):0 > ‘active_support’.from(3)
=> “ive_support”
1.9.3 (main):0 > ‘active_support’[3..-1]
=> “ive_support” # 同じ

30. blank?

31. blank?
1.9.3 (main):0 > nil.blank?
=> true
1.9.3 (main):0 > ''.blank?
=> true
1.9.3 (main):0 > ‘ ‘.blank?
=> true
1.9.3 (main):0 > ‘ ‘.blank?
=> true
1.9.3 (main):0 > ‘blank‘.blank?
=> false

32. present?

33. present?
1.9.3 (main):0 > true.present?
=> true
1.9.3 (main):0 > 'blank'.present?
=> true
1.9.3 (main):0 > ‘‘.present?
=> false
1.9.3 (main):0 > ‘ ‘.present?
=> false
1.9.3 (main):0 > nil.present?
=> false

34. presence

35. presence
1.9.3 (main):0 > true.presence
=> true
1.9.3 (main):0 > 'blank'.presence
=> 'blank'
1.9.3 (main):0 > ‘‘.presence
=> nil
1.9.3 (main):0 > ‘ ‘.presence
=> nil
1.9.3 (main):0 > nil.presence
=> nil

36. presence

37. presence
1.9.3 (main):0 > ‘cool’.presence || ‘oops!’
=> “cool”
1.9.3 (main):0 > ["aaa", "bbb", "ccc"].map{|x|
1.9.3 (main):0 * x.gsub("a","").presence &&
1.9.3 (main):0 * x.upcase}
=> [nil, "BBB", "CCC"]

38. inquiry

39. inquiry
1.9.3 (main):0 > ‘tiger’.inquiry
=> “tiger”
1.9.3 (main):0 > 'tiger'.inquiry.tiger?
=> true
1.9.3 (main):0 > 'tiger'.inquiry.bunny?
=> false
1.9.3 (main):0 > 'tiger'.inquiry.class
=> ActiveSupport::StringInquirer

40. どうやっているのか？
http://goo.gl/qt8Sz

41. DateTime系

42. Time.zone

43. Time.zone
1.9.3 (main):0 > Time.zone
=> nil
1.9.3 (main):0 > Time.zone = ‘Tokyo’
=> “Tokyo”
1.9.3 (main):0 > Time.zone
=> (GMT+09:00) Tokyo
1.9.3 (main):0 > Time.zone.now
=> Thu, 30 Aug 2012 17:41:49 JST +09:00

44. yesterday,tommorow

45. yesterday,tommorow
1.9.3 (main):0 > Time.zone.now
=> Thu, 30 Aug 2012 17:41:49 JST +09:00
1.9.3 (main):0 > Time.zone.now.tomorrow
=> Fri, 31 Aug 2012 17:41:49 JST +09:00
1.9.3 (main):0 > Time.zone.now.yesterday
=> Wed, 29 Aug 2012 17:41:49 JST +09:00

46. ago

47. ago
1.9.3 (main):0 > Time.zone.now
=> Thu, 30 Aug 2012 17:41:49 JST +09:00
1.9.3 (main):0 > 3.days.ago
=> Mon, 27 Aug 2012 17:41:49 JST +09:00
1.9.3 (main):0 > 10.month.ago
=> Sun, 30 Oct 2011 17:41:49 JST +09:00

48. since

49. since
1.9.3 (main):0 > Time.zone.now
=> Thu, 30 Aug 2012 17:41:49 JST +09:00
1.9.3 (main):0 > 3.days.since
=> Sun, 02 Sep 2012 17:41:49 JST +09:00
1.9.3 (main):0 > 10.month.since
=> Sun, 30 Jun 2013 17:41:49 JST +09:00

50. 引数

51. 引数
1.9.3 (main):0 > Time.zone.now
=> Thu, 30 Aug 2012 17:41:49 JST +09:00
1.9.3 (main):0 > Time.zone.now.ago(3.days)
=> Mon, 27 Aug 2012 17:41:49 JST +09:00
1.9.3 (main):0 > Time.zone.now.since(3.years)
=> Sun, 30 Aug 2015 17:41:49 JST +09:00

52. 始まりと終わり

53. 始まりと終わり
1.9.3 (main):0 > Time.zone.now
=> Thu, 30 Aug 2012 17:41:49 JST +09:00
1.9.3 (main):0 > Time.zone.now.beginning_of_day
=> Thu, 30 Aug 2012 00:00:00 JST +09:00
1.9.3 (main):0 > Time.zone.now.end_of_year
=> Mon, 31 Dec 2012 23:59:59 JST +09:00

54. 任意の時刻

55. 任意の時刻
1.9.3 (main):0 > Time.zone.now
=> Thu, 30 Aug 2012 17:41:49 JST +09:00
1.9.3 (main):0 > Time.zone.now.change(:hour =>
19)
=> Thu, 30 Aug 2012 19:00:00 JST +09:00

56. 範囲

57. 範囲
1.9.3 (main):0 > Time.zone.now
=> Thu, 30 Aug 2012 17:41:49 JST +09:00
1.9.3 (main):0 > Time.zone.now.all_day
=> 2012-08-30 00:00:00 UTC..2012-08-30 23:59:59
UTC
1.9.3 (main):0 > Time.now.all_day
=> 2012-08-30 00:00:00 +0900..2012-08-30 23:59:59
+0900

58. Array/Hash系

59. Array#from

60. Array#from
1.9.3 (main):0 > ‘cool’.presence || ‘oops!’
=> “cool”
1.9.3 (main):0 > ["aaa", "bbb", "ccc"].map{|x|
1.9.3 (main):0 * x.gsub("a","").presence &&
1.9.3 (main):0 * x.upcase}
=> [nil, "BBB", "CCC"]

61. Hash#assert_valid_keys

62. Hash#assert_valid_keys
1.9.3 (main):0 > hash = {
1.9.3 (main):0 * :tiger => 10.4,
1.9.3 (main):0 * :lion => 10.7
1.9.3 (main):0 * }
1.9.3 (main):0 > hash.assert_valid_keys(
1.9.3 (main):0 * :tiger, :leopard, :lion)
=> {:tiger=>10.5, :leopard=>10.6, :lion=>10.8}
1.9.3 (main):0 > hash.assert_valid_keys(
1.9.3 (main):0 * :tiger, :bunny)
=> ArgumentError: Unknown key: lion

63. Array#forty_two

64. Array#forty_two
1.9.3 (main):0 > [1,2,3,4].forty_two
=> nil
1.9.3 (main):0 > (1..100).to_a.forty_two
=> 42

65. なにこれ？

66. なにこれ？

67. 質疑応答

68. 質疑応答
if available?
Question.all.map{|x|
x.try(:answer).presence ||
x.to_a.forty_two}