Question

我一直试图让这段代码输出：

'Mary has a pet called Satan.'

但我得到的是：

'Mary has a pet called #<Cat:0x00000002784c20>'

以下代码：

class Person
    def initialize(name)
        @name = name
        @pet = nil
        @hobbies = []
    end

    def describe()
        puts "This persons name is #{@name}."
        puts "#{@name}'s hobbies are:"

        @hobbies.map { |hobby| puts hobby }

        if @pet == nil
            puts "#{@name} has not got any pets."
        else
            puts "#{@name} has a pet called #{@pet}"
        end
    end

    attr_accessor :pet, :hobbies
end
class Cat < Animal

def initialize(name)
    @name = name
end
end


satan = Cat.new("Satan")
mary = Person.new("Mary")
mary.pet = satan

mary.describe

感谢您的帮助。

Answer 1

在describe()函数中，您在不指定名称的情况下调用对象Cat。

但如果你打电话给#{pet.name}，它会抛出：

<undefined method `name' for #<Cat:0x0055d750a1a450 @name="Satan">

您必须先使用attr_accessor

允许访问name课程中的变量Cat

class Cat < Animal
  attr_accessor :name # First allow access

end


class Person
  def describe()
     puts "#{@name} has a pet called #{@pet.name}" # Then call the pet's name!
  end
end

如何在此字符串插值中获取字符串值

1 个答案: