Mysql 根据数据库中存在的值显示选择选项

如果数据库字段“day”中存在值“Monday”，则选择选项中不应出现值“Monday”。还有其他有效的方法吗？

<%= form_for(@timetable) do |f| %>     
<% Timetable.all.each do |t| %>
      <% if t.day == "Monday" %>
        <%= f.select :day, options_for_select(%w[Tuesday Wednesday Thursday Friday Saturday Sunday]) %>
      <% elsif t.day == "Tuesday" %>
        <%= f.select :day, options_for_select(%w[Wednesday Thursday Friday Saturday Sunday]) %>
      <% elsif t.day == "Wednesday" %>
        <%= f.select :day, options_for_select(%w[Thursday Friday Saturday Sunday]) %>
      <% elsif t.day == "Thursday" %>
        <%= f.select :day, options_for_select(%w[Friday Saturday Sunday]) %>
      <% elsif t.day == "Friday" %>
        <%= f.select :day, options_for_select(%w[Saturday Sunday]) %>
      <% elsif t.day == "Saturday" %>
        <%= f.select :day, options_for_select(%w[Sunday]) %>
      <% else %>
        <%= f.select :day, options_for_select(%w[Monday Tuesday Wednesday Thursday Friday Saturday Sunday]) %>
      <% end %>
<% end %>
<% end %>

---

我注释掉了循环，因为显示了多个选择框

这段代码不起作用，还是您正在寻找重构？代码不起作用，以及其他有效方法的方法什么是

@timeline

//代码在这里，请不要为问题添加答案（改为作为单独答案发布）。选择框应仅显示一次>选择框应仅显示一次，这与您的示例所示不同；）获取错误。nil:nilclass的未定义方法“-”实际上您得到了这个错误，因为您的“values”变量是nil@rinold，是否已将

值

变量插入到

符号中？我错过了那部分。

<% Timetable.all.each do |t| %>
  <%= f.select :day, options_for_select(%w[Sunday Saturday Friday Thursday Wednesday Tuesday Monday].take_while { |day| day != t.day }.reverse!, selected: @timetable.day ) %>
<% end %>

<% values = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"] %>
<%# Timetable.all.each do |t| %>
        <%= f.select :day, options_for_select(values - [@timetable.day], selected: @timetable.day ) %>
<%# end %>