Ruby 类，我怀疑我做错了实例标记

发布于 2024-11-18 16:23:55 字数 969 浏览 1 评论 0原文

我希望此类初始化以接收要保存的消息并为其输入文件名。我是否因为 Ruby 只希望在 init 方法中实例化值而导致错误？温柔一点，我是新手。回溯粘贴在下面。

class DobbsyKretts
  idea = 'arbitaryvalue'
  def initialize
    #Receive idea
    puts "Enter an idea, a secret or anything else you want to encrypt. Hit enter to stop typing and save the file"
    @idea.gets.reverse.upcase
    #Filename and saving - to encrypt the file.
    puts "Enter the file name you'd like to have this saved as. Type PLAN at the beginning for plans and REM for reminders"
    @file_name.gets.strip
    File::open("DobbsyKrett-"+ file_name + ".txt", "w") do |f|
      f>>@idea
    end
  end
end

something = DobbsyKretts.new

回溯：

testy.rb:11:in `initialize': private method `gets' called for nil:NilClass (NoMethodError)
    from testy.rb:21:in `new'
    from testy.rb:21:in `<main>'
Enter an idea, a secret or anything else you want to encrypt. Hit enter to stop typing and save the file

原文

I want this class to initialize to receive a message to be saved and enter a filename for it. Am I drawing up an error because Ruby only wants values to be instantiated in the init method? Be gentle, I'm new to this. Traceback pasted below.

class DobbsyKretts
  idea = 'arbitaryvalue'
  def initialize
    #Receive idea
    puts "Enter an idea, a secret or anything else you want to encrypt. Hit enter to stop typing and save the file"
    @idea.gets.reverse.upcase
    #Filename and saving - to encrypt the file.
    puts "Enter the file name you'd like to have this saved as. Type PLAN at the beginning for plans and REM for reminders"
    @file_name.gets.strip
    File::open("DobbsyKrett-"+ file_name + ".txt", "w") do |f|
      f>>@idea
    end
  end
end

something = DobbsyKretts.new

Traceback:

testy.rb:11:in `initialize': private method `gets' called for nil:NilClass (NoMethodError)
    from testy.rb:21:in `new'
    from testy.rb:21:in `<main>'
Enter an idea, a secret or anything else you want to encrypt. Hit enter to stop typing and save the file

分享到QQ

分享到微博

如果你对这篇内容有疑问，欢迎到本站社区发帖提问参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。

发布评论

需要登录才能够评论，你可以免费注册一个本站的账号。

夜雨飘雪 2024-11-25 16:23:55

您在分配值之前对 @idea 调用 gets - 这是您收到错误的原因之一。另外，不应在此处对实例变量调用 gets。像这样尝试一下：

class DobbsyKretts
  def initialize
    #Receive idea
    puts "Enter an idea, a secret or anything else you want to encrypt. Hit enter to stop typing and save the file"
    (@idea = gets).reverse.upcase
    #Filename and saving - to encrypt the file.
    puts "Enter the file name you'd like to have this saved as. Type PLAN at the beginning for plans and REM for reminders"
    @file_name = gets.strip
    File::open("DobbsyKrett-"+ @file_name + ".txt", "w") do |f|
      f << @idea
    end
  end
end

something = DobbsyKretts.new

这正如您所期望的那样工作，但我只是想提醒您，在构造函数中执行类似的操作是一个非常糟糕的主意。您应该使用专用方法来生成文件和/或要求用户输入。

You are calling getson @idea before having assigned a value - that's one of the reasons why you get the error. Also, gets should not be called on the instance variable here. Try it like this:

class DobbsyKretts
  def initialize
    #Receive idea
    puts "Enter an idea, a secret or anything else you want to encrypt. Hit enter to stop typing and save the file"
    (@idea = gets).reverse.upcase
    #Filename and saving - to encrypt the file.
    puts "Enter the file name you'd like to have this saved as. Type PLAN at the beginning for plans and REM for reminders"
    @file_name = gets.strip
    File::open("DobbsyKrett-"+ @file_name + ".txt", "w") do |f|
      f << @idea
    end
  end
end

something = DobbsyKretts.new

This works as you expected, but I just would like to remind you that it is a very bad idea to do something like this in the constructor. You should rather use a dedicated method for generating files and/or asking the user for input.

回复收藏 0 原文

梅倚清风 2024-11-25 16:23:55

gets 是 Kernel#gets 或 IO#gets （为简洁起见，我将省略 ARGF#gets），在您的情况下，@idea 不是 IO 对象（默认情况下，任何实例变量都设置为 nil），并且显式调用 Kernel#gets接收者被禁止。所以正确的代码是@idea = gets。