Forum: Ruby on Rails habtm > join()

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Zac E. (Guest)
on 2006-03-21 19:12
I'm trying to pull ou the 'name' field for each of my associated rows
and pass it as a string of names.  I'm missing something obvious here
but I thought  @bag.packages.name.join(", ") would work.

do I have to loop through @bag.packages?  that seems like the long way.

thanks

-zac
Jeff de Vries (Guest)
on 2006-03-21 19:18
(Received via mailing list)
I need a persistent message queue, similar to JMS.  Is there a
Rails/Ruby equivalent?
Josh S. (Guest)
on 2006-03-21 19:42
zac elston wrote:
> I'm trying to pull ou the 'name' field for each of my associated rows
> and pass it as a string of names.  I'm missing something obvious here
> but I thought  @bag.packages.name.join(", ") would work.
>
> do I have to loop through @bag.packages?  that seems like the long way.

You have to loop or do a custom query. Use the map message to do the
loop:

@bag.packages.map { |p| p.name }.join(", ")

In Edge/1.1 you can type that as @bag.packages.map(&:name).join(", ")

If you don't want to fetch all the package data but only get the list of
names, you'll have to construct a custom query using the :select option
on find(). This is probably a good use for an association extension.

--josh
http://blog.hasmanythrough.com
Wilson B. (Guest)
on 2006-03-21 19:48
(Received via mailing list)
On 3/21/06, Jeff de Vries <removed_email_address@domain.invalid> wrote:
> I need a persistent message queue, similar to JMS.  Is there a
> Rails/Ruby equivalent?
>

Check out ActiveMQ and Stomp:
http://activemq.codehaus.org/
http://stomp.codehaus.org/
http://rubyforge.org/projects/stomp/

You can use it simultaneously from various languages, including Ruby and
Java.
Justin F. (Guest)
on 2006-03-22 04:18
(Received via mailing list)
zac elston wrote:
> I'm trying to pull ou the 'name' field for each of my associated rows
> and pass it as a string of names.  I'm missing something obvious here
> but I thought  @bag.packages.name.join(", ") would work.
>
> do I have to loop through @bag.packages?  that seems like the long way.

You can't ask the packages collection for the names of all the packages
it contains. You do have to iterate over the collection, but it doesn't
involve a lot of code.

try

   @bag.packages.collect {|p| p.name}.join(', ')

regards

   Justin
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