前回 5.5まで(一部理解できてない) 特異メソッド a = [1,2,3] b = [1,2,3] c = a def a.xx self.inject(:+) end a.xx # => 6 b.xx # NoMethodError: undefined method `xx' for [1, 2, 3]:Array c.xx # => 6 [1,2,3].xx # NoMethodError: undefined method `xx' for [1, 2, 3]:Array c = a c.xx # => 6 c.clone.xx # => 6 …
