Rails - Apr 2006 - Sorting an array of models

I have a model, listing, which belongs_to one or more categories. I need 
the user to be able to search for categories by name (which I can do) 
and have it return all the listings that belong to those categories. 
This I can do.

However, what I need to do is take that list of listings and sort them 
by one of their fields. This is a bit more complicated, without needing 
to sort I could just do:

<% for category in @categories %>
   <% for listing in category.listings %>
        <%= DISPLAY CODE %>
   <% end %>
<% end %>

But now I need to get an array of listings in my controller code, and 
then sort that list. Is there an easy way to do that in Rails or do I 
need to write my own sort code?

Thanks,

-Adam

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On Apr 12, 2006, at 5:58 PM, Adam Bloom wrote:
> I have a model, listing, which belongs_to one or more categories. I  
> need
> the user to be able to search for categories by name (which I can do)
> and have it return all the listings that belong to those categories.
> This I can do.
>
> However, what I need to do is take that list of listings and sort them
> by one of their fields. This is a bit more complicated, without  
> needing
> to sort I could just do:
>
> <% for category in @categories %>
>    <% for listing in category.listings %>
>         <%= DISPLAY CODE %>
>    <% end %>
> <% end %>
>
> But now I need to get an array of listings in my controller code, and
> then sort that list. Is there an easy way to do that in Rails or do I
> need to write my own sort code?
>
> Thanks,
>
> -Adam
>
> -- 
> Posted via http://www.ruby-forum.com/.
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails

Look at Array#sort and Array#sort_by

-Ezra

Four ways to crack this nut.

1) retrieve the data from the database in the order you want it.  I  
think if you add an :order=>''column'' to the belongs_to
:category
statement in your ''listings.rb'' model file.  This should
default to this
sort order

2) use the association function: 
category.listings(:order=>''name'')

3) use a find statement: Listings.find_by_category(category,
:order=>''name'')

4) get the collection from the association function, and sort those

sorted_array = category.listings.sort {|a,b| a.name <=> b.name}

For the most part, I prefer to let the database do the sorting for me.

On Thursday, April 13, 2006, at 2:58 AM, Adam Bloom
wrote:
>I have a model, listing, which belongs_to one or more categories. I need
>the user to be able to search for categories by name (which I can do)
>and have it return all the listings that belong to those categories.
>This I can do.
>
>However, what I need to do is take that list of listings and sort them
>by one of their fields. This is a bit more complicated, without needing
>to sort I could just do:
>
><% for category in @categories %>
>   <% for listing in category.listings %>
>        <%= DISPLAY CODE %>
>   <% end %>
><% end %>
>
>But now I need to get an array of listings in my controller code, and
>then sort that list. Is there an easy way to do that in Rails or do I
>need to write my own sort code?
>
>Thanks,
>
>-Adam
>
>--
>Posted via http://www.ruby-forum.com/.
>_______________________________________________
>Rails mailing list
>Rails@lists.rubyonrails.org
>http://lists.rubyonrails.org/mailman/listinfo/rails

_Kevin

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Thanks for the responses!
> Four ways to crack this nut.
> 
> 1) retrieve the data from the database in the order you want it.  I
> think if you add an :order=>''column'' to the belongs_to
:category
> statement in your ''listings.rb'' model file.  This should
default to this
> sort order
This worked when I added the line to the line in categories.rb. I''m 
guessing because it''s actually a habtm. :)
> 2) use the association function: 
category.listings(:order=>''name'')
> 
> 3) use a find statement: Listings.find_by_category(category, 
> :order=>''name'')
> 
> 4) get the collection from the association function, and sort those
> 
> sorted_array = category.listings.sort {|a,b| a.name <=> b.name}
The problem with these is that I have to sort listings from 
(potentially) a bunch of different categories.
> For the most part, I prefer to let the database do the sorting for me.
>
> _Kevin
Thanks again,

Adam

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