drop down lists

Hi everyone,

I am now building a form, and for a field i want to give users only a small set of predetermined values. I implemented it as follows:

in the controller i created an array @ptypes = ["type a", "type b", ...]

in the _form <%= collection_select :purchase, :product, @ptypes, :to_s, :to_s %>

I am new to rails, and would like to know if there is a standard way for doing this. Thanks.