Ruby on rails 使用字符串和变量的Ruby switch语句比较无效

我在控制器中启动了一些变量，如下所示

 class ServicesController < ApplicationController
   before_action :set_service, only: [:show, :edit, :update, :destroy]
UPLOAD_N_DATA = "1", 
UPLOAD_T_DATA = "2", 
UPLOAD_C_DATA = "3", 
UPLOAD_E_DATA = "4",
UPLOAD_V_DATA = "5"

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为什么会这样？我认为这与对象比较有关。但是如何使用变量使其工作呢

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谢谢。

您使用尾随逗号定义常量，这是错误的，因为它将

['1'，'2'，'3'，'4'，'5']

数组分配给

上传数据

常量。应该是：

UPLOAD_N_DATA = "1"
UPLOAD_T_DATA = "2"
UPLOAD_C_DATA = "3"
UPLOAD_E_DATA = "4"
UPLOAD_V_DATA = "5"

   THIS WORKS:

   # GET /services/
   # GET /services/1.json
   def show
puts "Service Id received = #{params[:id]} of class #{params[:id].class}"
case(params[:id])
    when "1"
        puts "Service to upload N Data evoked"
    when "2"
        puts "Service to upload T Data evoked"
    when "3"
        puts "Service to upload C Data evoked"
    when "4"
        puts "Service to upload E Data evoked"
    when "5"
        puts "Service to upload C Data evoked"
    else
        puts "Error in Service Controller Show Services.\n Unknown Service Requested"
end
   end

UPLOAD_N_DATA = "1"
UPLOAD_T_DATA = "2"
UPLOAD_C_DATA = "3"
UPLOAD_E_DATA = "4"
UPLOAD_V_DATA = "5"