为什么删除不适用于full_messages函数？

Question

我有以下代码:

def register_learner
  @event = Event.find(params[:event_id])
  @registation = EventRegistration.new first_name: params[:first_name], last_name: params[:last_name], email: params[:email], event_id: params[:event_id]

  if !@registation.valid?
    @registation.errors.full_messages.delete("Event has already been taken"
    flash[:notice] = @registation.errors.full_messages.to_sentence
    redirect_to(event_path(@event))
  else
    @registation.save
  end
end

请注意@registation.errors.full_messages.delete("Event has already been taken")我尝试从full_messages数组中删除此特定消息的行,但它不起作用.下一行是flash消息,仍然显示消息"已经采取了事件".

这是通过控制台进行的健全性检查......

2.1.5 :001 > errors = ["Event has already been taken", "Last name can't be blank"]
 => ["Event has already been taken", "Last name can't be blank"]
2.1.5 :002 > errors.delete "Event has already been taken"
 => "Event has already been taken"
2.1.5 :003 > errors
 => ["Last name can't be blank"]

我错过了什么？

Answer 1

这是因为这full_messages是一种方法,每次调用它时都会生成一个新数组.做你想做的事:

errors = @registation.errors.full_messages
errors.delete("Event has already been taken")
flash[:notice] = errors.to_sentence

这回答了这个问题,现在有一个问题 - 为什么你需要这样做？可能有更好的方法.

一般来说,依赖字符串通常是一个坏主意,想象一下,在半年内,您需要更改此验证的错误消息.你能100%确定你会记得在这里改变它吗？如果没有,你有一个错误.