![ハッシュの例
{“?rst” => 1, “second” => 2, “third” => 3}
{?rst:1, second:2, third:3}
{“integer” => 1, “string” => ”text”, :array => [1, 2, 3]}](https://image.slidesharecdn.com/ruby-120524033203-phpapp02/85/Ruby-with-Hash-27-320.jpg)
![ハッシュの例
{“?rst” => 1, “second” => 2, “third” => 3}
{?rst:1, second:2, third:3} Ruby1.9以降
{“integer” => 1, “string” => ”text”, :array => [1, 2, 3]}](https://image.slidesharecdn.com/ruby-120524033203-phpapp02/85/Ruby-with-Hash-28-320.jpg)
![ハッシュの作り方
中身の入ったハッシュ
a = {“?rst” => 1, “second” => 2}
a = Hash.new(1) #=> {}
a = Hash[“?rst”, 1, “second”, 2]
a = Hash[*array]](https://image.slidesharecdn.com/ruby-120524033203-phpapp02/85/Ruby-with-Hash-34-320.jpg)
![要素の取り出し
a = {:alpha => "a", :bravo => "b", :charlie => "c"}
a[:alpha] #=> “a”
a.fetch(:bravo) #=> “b”
a.values #=> [“a”, “b”, “c”]](https://image.slidesharecdn.com/ruby-120524033203-phpapp02/85/Ruby-with-Hash-51-320.jpg)
![キーの取り出し
a = {:alpha => "a", :bravo => "b", :charlie => "c"}
a.keys #=> [:alpha, :bravo, :charlie]](https://image.slidesharecdn.com/ruby-120524033203-phpapp02/85/Ruby-with-Hash-54-320.jpg)
![要素とキーの取り出し
a = {:alpha => "a", :bravo => "b", :charlie => "c"}
a.?rst #=> [:alpha, “a”]
a.assoc(:bravo) #=> [:bravo, “b”]
a.shift #=> [:alpha, “a”]
a.to_a #=> [[:alpha, “a”], [:bravo, “b”], [:charlie, “c”]]](https://image.slidesharecdn.com/ruby-120524033203-phpapp02/85/Ruby-with-Hash-57-320.jpg)
![要素とキーの取り出し
a = {:alpha => "a", :bravo => "b", :charlie => "c"}
a.?rst #=> [:alpha, “a”]
a.assoc(:bravo) #=> [:bravo, “b”]
a.shift #=> [:alpha, “a”] 要素が削除される
a.to_a #=> [[:alpha, “a”], [:bravo, “b”], [:charlie, “c”]]](https://image.slidesharecdn.com/ruby-120524033203-phpapp02/85/Ruby-with-Hash-58-320.jpg)
![要素の追加?更新
a = {:alpha => "a", :bravo => "b", :charlie => "c"}
a[:delta] = “d”](https://image.slidesharecdn.com/ruby-120524033203-phpapp02/85/Ruby-with-Hash-61-320.jpg)
![イテレーション
a = {:alpha => "a", :bravo => "b", :charlie =>
"c"}
a.each_key do |k|
p k
p a[k]
end
a.each_value do |v|
p v
end](https://image.slidesharecdn.com/ruby-120524033203-phpapp02/85/Ruby-with-Hash-78-320.jpg)
![イテレーション
a = {:alpha => "a", :bravo => "b", :charlie =>
"c"}
a.each_key do |k|
p k
ブロック変数
p a[k]
end
a.each_value do |v|
p v
end](https://image.slidesharecdn.com/ruby-120524033203-phpapp02/85/Ruby-with-Hash-79-320.jpg)
![イテレーション
a = {:alpha => "a", :bravo => "b", :charlie =>
"c"}
a.each_key do |k|
p k
ブロック変数
p a[k]
end
a.each_value do |v|
p v
ブロック変数
end](https://image.slidesharecdn.com/ruby-120524033203-phpapp02/85/Ruby-with-Hash-80-320.jpg)
![応用编
無名ハッシュを返すメソッド
def const_hash
{
eagle: 15,
falcon: 16,
hornet: 18,
}
end
const_hash[:eagle] #=> 15](https://image.slidesharecdn.com/ruby-120524033203-phpapp02/85/Ruby-with-Hash-83-320.jpg)
![応用编
無名ハッシュを返すメソッド
def const_hash 初期設定などに便利
{
eagle: 15,
falcon: 16,
hornet: 18,
}
end
const_hash[:eagle] #=> 15](https://image.slidesharecdn.com/ruby-120524033203-phpapp02/85/Ruby-with-Hash-84-320.jpg)
![応用编
無名ハッシュを返すメソッド
const_hash[:eagle] = “15E”
const_hash[:eagle] #=> 15
const_hash[:cobra] = 17
const_hash[:cobra] #=> nil](https://image.slidesharecdn.com/ruby-120524033203-phpapp02/85/Ruby-with-Hash-87-320.jpg)
![応用编
無名ハッシュを返すメソッド
const_hash[:eagle] = “15E”
const_hash[:eagle] #=> 15
const_hash[:cobra] = 17
const_hash[:cobra] #=> nil
呼び出すたびに初期値が返る](https://image.slidesharecdn.com/ruby-120524033203-phpapp02/85/Ruby-with-Hash-88-320.jpg)
![Let’s Try!
ハッシュの値を全てStringにする
data = {
showa: 1926,
meiji: 1868,
taisho: 1912,
heisei: 1989,
}
Hash[*data.to_a.map{|x| [x.first, x.last.to_s]}]
# => {:showa => “1926”, :meiji => “1868”,...}](https://image.slidesharecdn.com/ruby-120524033203-phpapp02/85/Ruby-with-Hash-99-320.jpg)
![Let’s Try!
ハッシュを値でソートしてキーを返す
data = {
showa: 1926,
meiji: 1868,
taisho: 1912,
heisei: 1989,
}
# => [:meiji, :taisho, :showa, :heisei]](https://image.slidesharecdn.com/ruby-120524033203-phpapp02/85/Ruby-with-Hash-103-320.jpg)
![Let’s Try!
ハッシュを値でソートしてキーを返す
data = {
showa: 1926,
meiji: 1868,
taisho: 1912,
heisei: 1989,
}
data.invert.sort.map{|x| x.last}
# => [:meiji, :taisho, :showa, :heisei]](https://image.slidesharecdn.com/ruby-120524033203-phpapp02/85/Ruby-with-Hash-107-320.jpg)
![Let’s Try!
二つの配列からハッシュを作成する
array_a = [:meiji, :taisho, :showa, :heisei]
array_b = [1868, 1912, 1926, 1989]
# => {:meiji => 1868, :taisho => 1912,...}](https://image.slidesharecdn.com/ruby-120524033203-phpapp02/85/Ruby-with-Hash-111-320.jpg)
![Let’s Try!
二つの配列からハッシュを作成する
array_a = [:meiji, :taisho, :showa, :heisei]
array_b = [1868, 1912, 1926, 1989]
Hash[*array_a.map{
|x| [x, array_b[array_a.index(x)]]
}.flatten]
# => {:meiji => 1868, :taisho => 1912,...}](https://image.slidesharecdn.com/ruby-120524033203-phpapp02/85/Ruby-with-Hash-115-320.jpg)
![Let’s Try!
二つのハッシュをマージして値の大きい方だけを残す
hash_a = {meiji: 45, taisho: 1926,
showa: 64, :heisei => 2012}
hash_b = {meiji: 1912, taisho: 15,
showa: 1989, :heisei => 24}
hash_a.merge(hash_b){|k,a,b| [a,b].sort.last}
# => {:meiji => 1912, :taisho => 1926,...}](https://image.slidesharecdn.com/ruby-120524033203-phpapp02/85/Ruby-with-Hash-123-320.jpg)
Ruby with Hash
- 1. Ruby with Hash 2012/5/24 yoyogi.rb
- 5. 変数名まとめ
- 8. 変数名まとめ ローカル変数 a hoge 英数と_のみ under_score 一文字目は小文字 camelCase ms06
- 9. 変数名まとめ
- 10. 変数名まとめ
- 11. 変数名まとめ インスタンス変数
- 13. 変数名まとめ インスタンス変数 @a @hoge @で始まる @under_score @camelCase @ms06
- 14. 変数名まとめ
- 15. 変数名まとめ
- 16. 変数名まとめ クラス変数
- 18. 変数名まとめ クラス変数 @@a @@hoge @@で始まる @@under_score あまり使わない @@camelCase @@ms06
- 19. 変数名まとめ
- 20. 変数名まとめ
- 21. 変数名まとめ 定数
- 23. 変数名まとめ 定数 A Hoge 大文字で始まる Under_score 変更しようとすると警告 （変更できないわけではない） CamelCase MS06
- 24. 変数名まとめ
- 25. ここから本题
- 27. ハッシュの例 {“?rst” => 1, “second” => 2, “third” => 3} {?rst:1, second:2, third:3} {“integer” => 1, “string” => ”text”, :array => [1, 2, 3]}
- 28. ハッシュの例 {“?rst” => 1, “second” => 2, “third” => 3} {?rst:1, second:2, third:3} Ruby1.9以降 {“integer” => 1, “string” => ”text”, :array => [1, 2, 3]}
- 29. ハッシュの作り方
- 30. ハッシュの作り方 空のハッシュ
- 31. ハッシュの作り方 空のハッシュ a = {} a = Hash.new
- 32. ハッシュの作り方
- 34. ハッシュの作り方 中身の入ったハッシュ a = {“?rst” => 1, “second” => 2} a = Hash.new(1) #=> {} a = Hash[“?rst”, 1, “second”, 2] a = Hash[*array]
- 35. シンボル
- 37. シンボル シンボルをキーにすることが多い {:?rst => 1, :second => 2, :third => 3} {?rst:1, second:2, third:3}
- 38. シンボル？
- 40. シンボル？ Rubyの内部実装では、メソッド名や変数名、定数名、クラス名など の`名前'を 整数で管理しています。これは名前を直接文字列として処理するよりも 速度面 で有利だからです。そしてその整数をRubyのコード上で表現したものがシンボ ルです。 シンボルは、ソース上では文字列のように見え、内部では整数として扱われる、 両者を仲立ちするような存在です。 from Rubyリファレンスマニュアル
- 41. シンボル？
- 42. シンボル？
- 45. シンボル？ 文字列の前に:を付ける :a :hoge 読みやすい :under_score 書き換えられない ちょっと速い（かも知れない） :CamelCase :ms06
- 46. シンボル？
- 47. ハッシュの使い方
- 48. ハッシュの使い方 # all versions 1.9.x only a = {:alpha => "a", :bravo => "b", :charlie => "c"} # 1.9.x only a = {alpha: "a", bravo: "b", charlie: "c"}
- 49. 要素の取り出し
- 50. 要素の取り出し a = {:alpha => "a", :bravo => "b", :charlie => "c"}
- 51. 要素の取り出し a = {:alpha => "a", :bravo => "b", :charlie => "c"} a[:alpha] #=> “a” a.fetch(:bravo) #=> “b” a.values #=> [“a”, “b”, “c”]
- 52. キーの取り出し
- 53. キーの取り出し a = {:alpha => "a", :bravo => "b", :charlie => "c"}
- 54. キーの取り出し a = {:alpha => "a", :bravo => "b", :charlie => "c"} a.keys #=> [:alpha, :bravo, :charlie]
- 55. 要素とキーの取り出し
- 56. 要素とキーの取り出し a = {:alpha => "a", :bravo => "b", :charlie => "c"}
- 57. 要素とキーの取り出し a = {:alpha => "a", :bravo => "b", :charlie => "c"} a.?rst #=> [:alpha, “a”] a.assoc(:bravo) #=> [:bravo, “b”] a.shift #=> [:alpha, “a”] a.to_a #=> [[:alpha, “a”], [:bravo, “b”], [:charlie, “c”]]
- 58. 要素とキーの取り出し a = {:alpha => "a", :bravo => "b", :charlie => "c"} a.?rst #=> [:alpha, “a”] a.assoc(:bravo) #=> [:bravo, “b”] a.shift #=> [:alpha, “a”] 要素が削除される a.to_a #=> [[:alpha, “a”], [:bravo, “b”], [:charlie, “c”]]
- 59. 要素の追加?更新
- 60. 要素の追加?更新 a = {:alpha => "a", :bravo => "b", :charlie => "c"}
- 61. 要素の追加?更新 a = {:alpha => "a", :bravo => "b", :charlie => "c"} a[:delta] = “d”
- 62. ハッシュの评価
- 63. ハッシュの评価 a = {:alpha => "a", :bravo => "b", :charlie => "c"}
- 64. ハッシュの评価 a = {:alpha => "a", :bravo => "b", :charlie => "c"} a.has_key?(:bravo) #=> true a.empty? #=> false
- 65. ハッシュの検索
- 66. ハッシュの検索 a = {:alpha => "a", :bravo => "b", :charlie => "c"}
- 67. ハッシュの検索 a = {:alpha => "a", :bravo => "b", :charlie => "c"} a.select{|k, v| k == :alpha && v == “a”}
- 68. ハッシュのマージ
- 69. ハッシュのマージ a = {:alpha => "a", :bravo => "b", :charlie => "c"} b = {:able => "A", :baker => "B", :charlie => "C"}
- 70. ハッシュのマージ a = {:alpha => "a", :bravo => "b", :charlie => "c"} b = {:able => "A", :baker => "B", :charlie => "C"} a.merge(b) a.merge!(b) a.update(b) a.merge({:charlie => “C”, :delta => “d”}) a.merge(b){|k, a, b| a + b}
- 71. ハッシュのマージ a = {:alpha => "a", :bravo => "b", :charlie => "c"} b = {:able => "A", :baker => "B", :charlie => "C"} a.merge(b) a.merge!(b) 破壊的メソッド a.update(b) a.merge({:charlie => “C”, :delta => “d”}) a.merge(b){|k, a, b| a + b}
- 72. ハッシュのマージ a = {:alpha => "a", :bravo => "b", :charlie => "c"} b = {:able => "A", :baker => "B", :charlie => "C"} a.merge(b) a.merge!(b) 破壊的メソッド a.update(b) 破壊的メソッド a.merge({:charlie => “C”, :delta => “d”}) a.merge(b){|k, a, b| a + b}
- 73. イテレーション
- 74. イテレーション a = {:alpha => "a", :bravo => "b", :charlie => "c"} a.each do |k, v| p k p v end a.each_pair do |k, v| p k p v end
- 75. イテレーション a = {:alpha => "a", :bravo => "b", :charlie => "c"} a.each do |k, v| p k ブロック変数 p v end a.each_pair do |k, v| p k p v end
- 76. イテレーション a = {:alpha => "a", :bravo => "b", :charlie => "c"} a.each do |k, v| p k ブロック変数 p v end a.each_pair do |k, v| p k ブロック変数 p v end
- 77. イテレーション
- 78. イテレーション a = {:alpha => "a", :bravo => "b", :charlie => "c"} a.each_key do |k| p k p a[k] end a.each_value do |v| p v end
- 79. イテレーション a = {:alpha => "a", :bravo => "b", :charlie => "c"} a.each_key do |k| p k ブロック変数 p a[k] end a.each_value do |v| p v end
- 80. イテレーション a = {:alpha => "a", :bravo => "b", :charlie => "c"} a.each_key do |k| p k ブロック変数 p a[k] end a.each_value do |v| p v ブロック変数 end
- 81. 応用编
- 83. 応用编 無名ハッシュを返すメソッド def const_hash { eagle: 15, falcon: 16, hornet: 18, } end const_hash[:eagle] #=> 15
- 84. 応用编 無名ハッシュを返すメソッド def const_hash 初期設定などに便利 { eagle: 15, falcon: 16, hornet: 18, } end const_hash[:eagle] #=> 15
- 87. 応用编 無名ハッシュを返すメソッド const_hash[:eagle] = “15E” const_hash[:eagle] #=> 15 const_hash[:cobra] = 17 const_hash[:cobra] #=> nil
- 88. 応用编 無名ハッシュを返すメソッド const_hash[:eagle] = “15E” const_hash[:eagle] #=> 15 const_hash[:cobra] = 17 const_hash[:cobra] #=> nil 呼び出すたびに初期値が返る
- 89. 応用编
- 90. 応用编
- 92. 応用编 引数にハッシュを取るメソッド def args_by_hash(params = {}) options = {:tiger => 88, :panther => 75}.merge! (params) p options end args_by_hash(mouse: 128) #=> {:tiger => 88, :panther => 75, :mouse => 128} args_by_hash(:tiger => 128, :panther => 88, :long => 75) #=> {:tiger => 128, :panther => 88, :lang => 75}
- 93. Let’s Try!
- 95. Let’s Try! ハッシュの値を全てStringにする data = { showa: 1926, meiji: 1868, taisho: 1912, heisei: 1989, } # => {:showa => “1926”, :meiji => “1868”,...}
- 96. Let’s Try!
- 97. Let’s Try!
- 99. Let’s Try! ハッシュの値を全てStringにする data = { showa: 1926, meiji: 1868, taisho: 1912, heisei: 1989, } Hash[*data.to_a.map{|x| [x.first, x.last.to_s]}] # => {:showa => “1926”, :meiji => “1868”,...}
- 100. Let’s Try!
- 101. Let’s Try!
- 103. Let’s Try! ハッシュを値でソートしてキーを返す data = { showa: 1926, meiji: 1868, taisho: 1912, heisei: 1989, } # => [:meiji, :taisho, :showa, :heisei]
- 104. Let’s Try!
- 105. Let’s Try!
- 107. Let’s Try! ハッシュを値でソートしてキーを返す data = { showa: 1926, meiji: 1868, taisho: 1912, heisei: 1989, } data.invert.sort.map{|x| x.last} # => [:meiji, :taisho, :showa, :heisei]
- 108. Let’s Try!
- 109. Let’s Try!
- 111. Let’s Try! 二つの配列からハッシュを作成する array_a = [:meiji, :taisho, :showa, :heisei] array_b = [1868, 1912, 1926, 1989] # => {:meiji => 1868, :taisho => 1912,...}
- 112. Let’s Try!
- 113. Let’s Try!
- 115. Let’s Try! 二つの配列からハッシュを作成する array_a = [:meiji, :taisho, :showa, :heisei] array_b = [1868, 1912, 1926, 1989] Hash[*array_a.map{ |x| [x, array_b[array_a.index(x)]] }.flatten] # => {:meiji => 1868, :taisho => 1912,...}
- 116. Let’s Try!
- 117. Let’s Try!
- 119. Let’s Try! 二つのハッシュをマージして値の大きい方だけを残す hash_a = {meiji: 45, taisho: 1926, showa: 64, :heisei => 2012} hash_b = {meiji: 1912, taisho: 15, showa: 1989, :heisei => 24} # => {:meiji => 1912, :taisho => 1926,...}
- 120. Let’s Try!
- 121. Let’s Try!
- 123. Let’s Try! 二つのハッシュをマージして値の大きい方だけを残す hash_a = {meiji: 45, taisho: 1926, showa: 64, :heisei => 2012} hash_b = {meiji: 1912, taisho: 15, showa: 1989, :heisei => 24} hash_a.merge(hash_b){|k,a,b| [a,b].sort.last} # => {:meiji => 1912, :taisho => 1926,...}
- 124. Let’s Try!
- 126. 质疑応答
- 128. ご清聴ありがとうございました
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