How to group a list of symbols or numbers into a # symbol

I am trying to create a glossary of terms ordered alphabetically like this example:

 -A-
 Alpha
 ATM

 -B-
 Beta
 ...

I have no problem to group terms by letter but I wonder how I can manage symbol and digits in order to group them through a # symbol

-#-
52 weeks low
@test

I figured out to add a column in my Term tab开发者_开发技巧le where I specify the first letter (in the symbol case I would select a "#" in a select box for example) but I would be pleased to know if there is a better way to achieve this without adding another field.

As info, here is my controller:

@terms = Term.all.group_by{|t| t.name[0]}

and my view:

<% @terms.keys.sort.each do |first_letter| %>
  <%= first_letter %>
  <% @terms[first_letter].each do |term| %>
    <%= term.name %>
  <% end %>
<% end %>

Thanks for your help!

---

You can do it like this, might be a performance hit, but gets the job done:

@terms = Term.all.group_by{|t| t.name[0].capitalize.match(/[A-Z]/) ? t.name[0].capitalize : "#" }