Question

我尝试使用movies方法迭代thumbs_up数组并将其打印到屏幕上。

class Movie
  def initialize(title,rank)
    @title=title
    @rank=rank
  end
  def thumbs_up
    @rank+=1
  end
  def to_s
    puts "your title is #{@title.to_s} and its rank is #{@rank.to_s} "
  end
end

movie1 = Movie.new("Goonies", 6)
movie2 = Movie.new("Spun", 3)
movie3 = Movie.new("Hook", 2)
movies = [movie1, movie2, movie3]
movies.each do |x|
  puts x.thumbs_up
  puts x
end

我在输出后得到了像字符这样的额外错误。这是大部分正确的输出，但在我想要的输入后包含额外的东西：

your title is Goonies and its rank is 7 
#<Movie:0x007fa6ba0e1da8>
4
your title is Spun and its rank is 4 
#<Movie:0x007fa6ba0e1d58>
3
your title is Hook and its rank is 3 
#<Movie:0x007fa6ba0e1d08>

我需要更改或删除它？

Answer 1

您引用的输出实际上并非像“类似错误”字符那样的字符＆＃39;。它是一个对象。一种方法是从puts方法中移除to_s，但是除了修改其直接表示（例如，以某种格式输出某些内容）之外，它通常被认为是不好的做法。输出它作为句子的一部分）。更好，更模块化的方法如下：

class Movie
  def initialize(title,rank)
    @title = title
    @rank = rank
  end

  def thumbs_up
    @rank+=1
  end

  def thumbs_down
    @rank-=1
  end

  attr_reader :title, :rank
  attr_accessor :title
end

movie1 = Movie.new("Goonies",6)
movie2 = Movie.new("Spun",3)
movie3 = Movie.new("Hook",2)
movies = [movie1 ,movie2, movie3]

movies.each do |x|
  x.thumbs_up
  puts "Your title is #{x.title} and its rank is #{x.rank}"
end

这输出以下内容：

Your title is Goonies and its rank is 7
Your title is Spun and its rank is 4
Your title is Hook and its rank is 3

这可以通过attr_reader类中的Movie语句使用您公开的属性来实现。

Answer 2

尝试从puts方法移除to_s。

输出中有类似错误的字符

2 个答案: