ruby nil让我困惑

Question

我从昨天开始学习Ruby.以下是我的疑问:

class MegaGreeter
      attr_accessor :names

      def intialize(names="World!")
        @names = names
      end

      def say_test
        if @names.nil?
          puts "nil test..."
        end
      end  

    end


    megaGreeter = MegaGreeter.new
    megaGreeter.say_test // Here showing ouput as "nil test..." 

起初我只是assuming 'nil' almost like 'null' in java.但我的假设在上述情况下似乎是错误的.

我不明白为什么在上面if @names.nil returning as TRUE？,@names will have a value "World!"既然如此,@ names如何视为null？

我已经搜索了' nil',但我真的没有清楚地了解它.

Answer 1

你有一个错字.#intialize应该是initialize.

看到,

class MegaGreeter
  attr_accessor :names

  def initialize(names = "World!")
    @names = names
  end

  def say_test
    if @names.nil?
      puts "nil test..."
    else
      puts "@names is not holding nil"
    end
  end  
end

megaGreeter = MegaGreeter.new
megaGreeter.say_test # => @names is not holding nil
megaGreeter = MegaGreeter.new(nil)
megaGreeter.say_test # => nil test...