Question

在我的程序中我得到一个错误，上面写着./ruby_camping.rb:91:in` - '：nil无法强制进入Fixnum（TypeError）。我想做的是结账我刚签到的客人。以下是结账部分的代码块：

def self.check_out 
  puts "Welcome to checkout!"
  puts $camping.current_guests
  puts " Here are the current guests, who do you want to checkout?!" 
  puts "State plot number "
  plot = gets.chomp.to_i
  guest = $camping.current_guests[plot-1] 
  puts "State the date for your checkout (a number bigger then " + guest.arrived.to_s + "): "
  # it should not be possible for a guest to checkout before she has checked in
  departureDate = gets.chomp.to_i
  guestStayedDays = departureDate - guest.arrived #Days the guest has stayed
  while (guestStayedDays < 1) do                        
   puts "The date for checkout is not valid. The guest checked in " + guest.arrived.to_s
   puts "Please state a new date."
   departureDate = gets.chomp.to_i
   guestStayedDays = departureDate - guest.arrived
  end       
  guest.departure = departureDate
  guest.plot.increase(guestStayedDays) # increases the electricity meter
  puts guest # prints the guest
  $camping.current_guests[plot-1] = nil # emptys the plot
 end
end

为什么离开日期仍然是零？感谢您的帮助！

Answer 1

要获得更详细的答案，您必须指明程序中第91行是哪一行。但是，为了指出正确的方向，如果您看到nil can't be coerced into Fixnum，则表示-的右侧的某些内容为nil。 e.g。

irb(main):001:0> 5 - nil
TypeError: nil can't be coerced into Fixnum
        from (irb):1:in `-'
        from (irb):1

从您的代码中我可以看到的唯一可能的示例是guestStayedDays = departureDate - guest.arrived，因此我会检查guest.arrived的值。

如果-的左侧上的内容为nil，例如departureDate或plot然后您将获得undefined method '-' for nil:NilClass。

` - '：nil不能被强制转换为Fixnum（TypeError）

1 个答案: