[Rails] (no subject)

[dblack at wobblini.net]

Hi --

On Fri, 10 Feb 2006, Peter T Bosse II wrote:

> I am trying to populate a select() popup menu with all of the currently 
> entered options from the database.  My thinking is that I would search the 
> database for all records, then call my "get_options" with the name of the 
> field as an argument.
>
> def list
>   @assets = Asset.find(:all)
>   get_options(@assets,"asset_type")
> end
>
> private
> def get_options(items,field)
>   @options = []
>   items.each do |@item|
>     @options << @item.field
>   end
>   @options = @options.sort.uniq
> end
>
> This doesn't work.  However, if I replace:
>
>     @options << @item.field
>
> with:
>
>     @options << @item.asset_type
>
> (...where "asset_type" is the name of a field in the database) it does work. 
> Now, I'm trying to follow the DRY principles, but I can't figure out how to 
> pass the field name to "get_options".  I could write a dozen or so 
> "get_options_asset_type", "get_options_serial_number" and the like and it 
> would work, but this is an opportunity for me to learn.  How am I supposed to 
> do this?

You can use send:

   @options << @item.send(field)

You could tighten up the method a bit if you like (untested rewrite
follows):

   def get_options(items,field)
     @options = items.map {|item| item.send(field) }.sort.uniq
   end

(I've changed @item to item as it wasn't clear why that would need to
be an instance variable.)


David

-- 
David A. Black (dblack at wobblini.net)
Ruby Power and Light (http://www.rubypowerandlight.com)

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