WEB開発をやり始めてみる(Ruby:配列＋いろんなメソッド)

やったことメモ

配列を使ったメソッドの使い方のまとめ

$ irb
#### 配列の書き方
2.5.0 :001 > a = [1, 2, 3, 'aa', [1, 2, 3]]
 => [1, 2, 3, "aa", [1, 2, 3]]

#### 配列の表示の仕方
2.5.0 :002 > a[0]
 => 1 
2.5.0 :003 > a[1]
 => 2 
2.5.0 :004 > puts a
1
2
3
aa
1
2
3
 => nil 

#### 配列の中身が空かどうか
2.5.0 :005 > a.empty?
 => false 
2.5.0 :006 > b = []
 => [] 
2.5.0 :007 > b.empty?
 => true

#### 配列の中身に〇〇が含まれているか
2.5.0 :008 > a.include?('aa')
 => true 
2.5.0 :009 > a.include?('b')
 => false 

#### 配列の中身を逆順に表示(!を使うと破壊的メソッドといって、元の中身を書き換える)
2.5.0 :010 > a.reverse
 => [[1, 2, 3], "aa", 3, 2, 1] 
2.5.0 :011 > a
 => [1, 2, 3, "aa", [1, 2, 3]] 
2.5.0 :012 > a.reverse!
 => [[1, 2, 3], "aa", 3, 2, 1] 
2.5.0 :013 > a
 => [[1, 2, 3], "aa", 3, 2, 1] 

#### 配列の中身をシャッフルして表示
2.5.0 :014 > a.shuffle
 => [1, 2, "aa", [1, 2, 3], 3] 
2.5.0 :015 > a.shuffle
 => ["aa", 1, 3, [1, 2, 3], 2] 
2.5.0 :016 > a
 => [[1, 2, 3], "aa", 3, 2, 1]

#### 配列を作る(.to_a) (0..25)は0 - 25といった範囲を指定
 2.5.0 :019 > (0..25).to_a
 => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25] 
2.5.0 :020 > aa = (0..99).to_a.shuffle!
 => [49, 76, 39, 50, 52, 17, 12, 21, 97, 0, 67, 59, 56, 32, 11, 64, 72, 9, 95, 73, 92, 58, 78, 28, 37, 31, 90, 93, 4, 8, 60, 2, 47, 66, 74, 42, 6, 84, 7, 10, 63, 75, 36, 33, 3, 53, 35, 19, 5, 77, 23, 48, 38, 81, 15, 57, 13, 27, 24, 16, 1, 70, 98, 87, 20, 80, 79, 88, 40, 30, 26, 99, 83, 61, 18, 82, 54, 89, 46, 29, 68, 14, 71, 25, 41, 91, 85, 96, 51, 94, 22, 69, 62, 45, 65, 34, 44, 43, 55, 86] 
2.5.0 :021 > aa
 => [49, 76, 39, 50, 52, 17, 12, 21, 97, 0, 67, 59, 56, 32, 11, 64, 72, 9, 95, 73, 92, 58, 78, 28, 37, 31, 90, 93, 4, 8, 60, 2, 47, 66, 74, 42, 6, 84, 7, 10, 63, 75, 36, 33, 3, 53, 35, 19, 5, 77, 23, 48, 38, 81, 15, 57, 13, 27, 24, 16, 1, 70, 98, 87, 20, 80, 79, 88, 40, 30, 26, 99, 83, 61, 18, 82, 54, 89, 46, 29, 68, 14, 71, 25, 41, 91, 85, 96, 51, 94, 22, 69, 62, 45, 65, 34, 44, 43, 55, 86] 
2.5.0 :022 > z = (0..10).to_a
 => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10] 

#### 配列の後ろに足す(pushも同様)
2.5.0 :023 > z << 20
 => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20] 
2.5.0 :024 > z
 => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20] 
2.5.0 :025 > z.push(30)
 => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30] 
2.5.0 :027 > z
 => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30] 

#### 配列の後ろを削除
2.5.0 :028 > z.pop
 => 30 
2.5.0 :030 > z
 => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20] 
2.5.0 :031 > z.shift
 => 0 
2.5.0 :032 > z
 => [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20] 
2.5.0 :033 > z << 3
 => [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 3] 
2.5.0 :034 > z << 6
 => [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 3, 6] 

#### 配列の中身で一緒になっていないものを表示（被っていない）
2.5.0 :035 > z.uniq
 => [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20] 
2.5.0 :036 > z
 => [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 3, 6] 
2.5.0 :037 > z.uniq!
 => [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20] 
2.5.0 :038 > z
 => [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20] 

#### 配列の中身を結合&どう結合をするか
2.6.3 :007 > s = ["my","name","is","kuruma"]
 => ["my", "name", "is", "kuruma"] 
2.6.3 :008 > s.join
 => "mynameiskuruma" 
2.6.3 :009 > s.join(" ")
 => "my name is kuruma" 
2.6.3 :010 > s.join("_")
 => "my_name_is_kuruma"