From: Rob Biedenharn <Rob@...>
Date: 2010-11-15T21:26:56+09:00
Subject: Re: FasterCSV

On Nov 14, 2010, at 10:48 PM, Francisca Munhoz wrote:

> Hi I'm learning Ruby, so I have a beginners question for you:
>
> How Can I sort attributes.values for similar order as csv_header? Just
> consider that I already order by csv_header on my query but i did not
> work.
>
> @custom_csv = User.find(:all, :select=>"name, lastname, address  
> " :order
> => "name, lastname, address")
>
> csv_header = [name,lastname,address]
>
> csv_string = FasterCSV.generate do |csv|
>
> csv << csv_header
>
> @custom_csv.each do |v|
>
> csv << v.attributes.values
>
> end
>
> end
>
> Thanks in advance!


Well, since you've already limited the attributes that ActiveRecord  
will see (assuming by your syntax that User is a model derived from  
ActiveRecord::Base), then v.attributes will be a hash that contains  
just those three key/value pairs.

Your definition of the headers probably needs to be something like:
	csv_header = %w[ name lastname address ]
but then the statement in the inner loop can be:
	csv << v.attributes.values_at(*csv_header)
You can lookup the docs for Hash#values_at and the * is the "unary  
unarray" operator or the "splat" which places the elements of  
csv_header into the argument list separately.  This is equivalent to:
	csv << v.attributes.values_at("name","lastname","address")

If you have other questions that get more Rails-specific, I'd suggest  
jumping over to the rails list.
http://groups.google.com/group/rubyonrails-talk?hl=en

-Rob

Rob Biedenharn		
Rob@AgileConsultingLLC.com	http://AgileConsultingLLC.com/
rab@GaslightSoftware.com		http://GaslightSoftware.com/