ruby-on-rails - Rails - 如何创建字母系统？

Question

我正在使用 Ruby on Rails 从我的 mySQL 数据库获取数据:

def all_specs
   Specialization.order("title ASC").all;
end

现在，我想像这样在 View 文件中对这些数据进行排序:

 <div class="nav-column">
   <h3>A</h3>
    <ul class="submenu">
        <li><a href="#">All data that has title that starts with A</a></li>
    </ul>
</div>   

 <div class="nav-column">
   <h3>A</h3>
    <ul class="submenu">
        <li><a href="#">All data that has title that starts with B</a></li>
    </ul>
</div>   

and so on from A-Z

我怎样才能做到这一点？

Answer 1

您可以对数据进行分组:

specs = Specialization.order("title ASC")
specs_by_first_letter = specs.group_by { |spec| spec.title[0] }

这会返回一个散列，如下所示:

{
  "A" => [<Specialization title:"A...">, <Specialization title:"A...">],
  "B" => [<Specialization title:"B...">, <Specialization title:"B...">],
  ...
  "Z" => [<Specialization title:"Z...">, <Specialization title:"Z...">]
}

遍历这个散列应该很容易。请注意，某些字母可能会丢失。