Rails - Sep 2008 - a simple way to generate a comma separated list of codes?

I have a model, Account, with many Courses. I want to display the course
codes for those courses as comma delimited text in an attribute of the
account. So I would have

Account << ActiveRecord::Base
has_many :courses

def get_course_codes_as_text
  courses.each {|course| something something but I don''t know what
end

Now I could do it the hard way by setting up a string var and pumping
stuff into it inside the block. But there''s an easier Rubyesque way to
do this which I''ve seen in code elsewhere but I can''t find the
code now
so I thought I''d ask here. Something to do with join or map or
something

John Small
-- 
Posted via http://www.ruby-forum.com/.

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On Tue, Sep 9, 2008 at 10:11 PM, John Small <
rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org> wrote:
>
> I have a model, Account, with many Courses. I want to display the course
> codes for those courses as comma delimited text in an attribute of the
> account. So I would have
>
> Account << ActiveRecord::Base
> has_many :courses
>
> def get_course_codes_as_text
>  courses.each {|course| something something but I don''t know what
> end
>
> Now I could do it the hard way by setting up a string var and pumping
> stuff into it inside the block. But there''s an easier Rubyesque
way to
> do this which I''ve seen in code elsewhere but I can''t
find the code now
> so I thought I''d ask here. Something to do with join or map or
something
>
> John Small
> --
> Posted via http://www.ruby-forum.com/.
>
> >
>
a = []
courses.each { |course|
a.push(course.code)
}
a = a.join ","


This ought to do it.


~~
Shiv

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On Tue, Sep 9, 2008 at 9:46 AM, Shiv N Gautam
<s.n.gautam-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>
>
> On Tue, Sep 9, 2008 at 10:11 PM, John Small <
> rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org> wrote:
>
>>
>> I have a model, Account, with many Courses. I want to display the
course
>> codes for those courses as comma delimited text in an attribute of the
>> account. So I would have
>>
>> Account << ActiveRecord::Base
>> has_many :courses
>>
>> def get_course_codes_as_text
>>  courses.each {|course| something something but I don''t know
what
>> end
>>
>> Now I could do it the hard way by setting up a string var and pumping
>> stuff into it inside the block. But there''s an easier
Rubyesque way to
>> do this which I''ve seen in code elsewhere but I can''t
find the code now
>> so I thought I''d ask here. Something to do with join or map or
something
>>
>> John Small
>> --
>> Posted via http://www.ruby-forum.com/.
>>
>>
>>
> a = []
> courses.each { |course|
> a.push(course.code)
> }
> a = a.join ","
>
>
> This ought to do it.
>
>
> ~~
> Shiv
>
> >
>
or.. (a bit more concise)

courses.collect(&:code).join('','')


-- 
Vince Hodges
http://www.imbas.ca/

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See if I qualify:

courses.collect {|c| c.code}.join(",")

John Small wrote:
> I have a model, Account, with many Courses. I want to display the course
> codes for those courses as comma delimited text in an attribute of the
> account. So I would have
> 
> Account << ActiveRecord::Base
> has_many :courses
> 
> def get_course_codes_as_text
>   courses.each {|course| something something but I don''t know what
> end
> 
> Now I could do it the hard way by setting up a string var and pumping
> stuff into it inside the block. But there''s an easier Rubyesque
way to
> do this which I''ve seen in code elsewhere but I can''t
find the code now
> so I thought I''d ask here. Something to do with join or map or
something
> 
> John Small
-- 
Posted via http://www.ruby-forum.com/.

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Newbie question: how do I prevent your code snippet from becoming an n-
fetch?

Eager loading will work, but if all I want are the codes, then eager
loading of the associated courses will over-retrieve data.

Yes, yes, I know - don''t over optimize. But if I know how to optimize,
at least I can put a comment in the code to remind me when I get
twitter-size traffic. :-)

-- Bosco


On Sep 9, 9:55 am, William Yeung
<rails-mailing-l...-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org>
wrote:
> See if I qualify:
>
> courses.collect {|c| c.code}.join(",")
>
>
>
> John Small wrote:
> > I have a model, Account, with many Courses. I want to display the
course
> > codes for those courses as comma delimited text in an attribute of the
> > account. So I would have
>
> > Account << ActiveRecord::Base
> > has_many :courses
>
> > def get_course_codes_as_text
> >   courses.each {|course| something something but I don''t know
what
> > end
>
> > Now I could do it the hard way by setting up a string var and pumping
> > stuff into it inside the block. But there''s an easier
Rubyesque way to
> > do this which I''ve seen in code elsewhere but I
can''t find the code now
> > so I thought I''d ask here. Something to do with join or map
or something
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William Yeung wrote:
> See if I qualify:
> 
> courses.collect {|c| c.code}.join(",")
> 
Yes, that''s the code snippet I was looking for!

Thanks

John Small


-- 
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