Ruby:NoMethodError，但为什么呢? [英] Ruby: NoMethodError, but why?

问题描述

我在学习 Ruby 时正在开发一个简单的 Pi 生成器，但是我在 RubyMine 6.3.3 上一直遇到 NoMethodError，所以我决定用尽可能简单的方式创建一个新项目和新类，并且我仍然 得到 NoMethodError.有什么理由吗?

I was working on a simple Pi Generator while learning Ruby, but I kept getting NoMethodError on RubyMine 6.3.3, so I decided to make a new project and new class with as simple as possible, and I STILL get NoMethodError. Any reason?

class Methods
  def hello (player)
    print "Hello, " << player
  end
  hello ("Annie")
end

我得到的错误是:

C:/Users/Annie the Eagle/Documents/Coding/Ruby/Learning Environment/methods.rb:5:in `<class:Methods>': undefined method `hello' for Methods:Class (NoMethodError)

推荐答案

您已经定义了一个实例方法，并试图将其作为一个类的方法来调用.因此，您需要使方法 hello 成为类方法，而不是 Methods 类的实例方法.

You have defined an instance method and are trying to call it as a method of a class. Thus you need to make the method hello a class method, not an instance method of the class Methods.

class Methods
  def self.hello(player)
    print "Hello, " << player
  end
  hello("Annie")
end

或者，如果您想将其定义为实例方法，则按如下方式调用它:

Or, if you want to define it as instance method then call it as below :

class Methods
  def hello(player)
    print "Hello, " << player
  end
end
Methods.new.hello("Annie")

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