# Sorting an array of models

**URL:** <https://www.ruby-forum.com/t/sorting-an-array-of-models/57692>\
**Category:** Rails\
**Created:** [April 13, 2006, 2:58am UTC](https://www.ruby-forum.com/t/sorting-an-array-of-models/57692 "2006-04-13T02:58:34Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![adambeazley](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/5f9b8f/32.png) [@adambeazley](https://www.ruby-forum.com/u/adambeazley)\
**Post date:** [April 13, 2006, 2:58am UTC](https://www.ruby-forum.com/t/sorting-an-array-of-models/57692/1 "2006-04-13T02:58:34Z")

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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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**Author:** ![adambeazley](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/5f9b8f/32.png) [@adambeazley](https://www.ruby-forum.com/u/adambeazley)\
**Post date:** [April 13, 2006, 3:15am UTC](https://www.ruby-forum.com/t/sorting-an-array-of-models/57692/2 "2006-04-13T03:15:47Z")

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On Apr 12, 2006, at 5:58 PM, Adam B. wrote:

> Thanks,
> 
> -Adam
> 
> –  
> Posted via [http://www.ruby-forum.com/](http://www.ruby-forum.com/).
> 
> * * *
> 
> Rails mailing list  
> removed\_email\_address@domain.invalid  
> [http://lists.rubyonrails.org/mailman/listinfo/rails](http://lists.rubyonrails.org/mailman/listinfo/rails)

Look at Array#sort and Array#sort\_by

-Ezra

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**Author:** ![adambeazley](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/5f9b8f/32.png) [@adambeazley](https://www.ruby-forum.com/u/adambeazley)\
**Post date:** [April 13, 2006, 3:18am UTC](https://www.ruby-forum.com/t/sorting-an-array-of-models/57692/3 "2006-04-13T03:18:49Z")

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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 B. wrote:

> \<% for listing in category.listings %\>  
> -Adam
> 
> –  
> Posted via [http://www.ruby-forum.com/](http://www.ruby-forum.com/).
> 
> * * *
> 
> Rails mailing list  
> removed\_email\_address@domain.invalid  
> [http://lists.rubyonrails.org/mailman/listinfo/rails](http://lists.rubyonrails.org/mailman/listinfo/rails)

\_Kevin

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<div class="post-metadata">

**Author:** ![adambeazley](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/5f9b8f/32.png) [@adambeazley](https://www.ruby-forum.com/u/adambeazley)\
**Post date:** [April 13, 2006, 3:58am UTC](https://www.ruby-forum.com/t/sorting-an-array-of-models/57692/4 "2006-04-13T03:58:31Z")

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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. 🙂

> 1. use the association function: category.listings(:order=\>‘name’)
> 
> 2. use a find statement: Listings.find\_by\_category(category,  
> :order=\>‘name’)
> 
> 3. 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