From: "David A. Black" <dblack@...>
Date: 2008-09-11T10:04:39+09:00
Subject: Re: Getting values from array of arrays

Hi --

On Thu, 11 Sep 2008, Allen Walker wrote:

> I have a drop down list in my view. In my model I have the following:

I'm guessing this is a Rails application :-)

> ARTICLE_CATEGORIES = [
>                        ["News", 1], ["Article", 2], ["Review", 3]
>                       ]
>
> validates_inclusion_of :category, :in => ARTICLE_CATEGORIES.map { |disp,
> value| value }
>
> I want to extract out all "Article" types in my controller.
>
> So in my controller: (I have a 'category' field in my 'articles' table)
>
> @news = Article.find_by_category(ARTICLE::ARTICLE_CATEGORIES.find...??)
>
> Not sure how to do this. I want to get the ID (in this case 2) from the
> ARTICLES_CATEGORIES array but I want to extract it out of this array
> using the key "Article".

You should use a hash, rather than an array.

   ARTICLE_CATEGORIES = { "News" => 1, "Article" => 2, "Review" => 3 }

   @news = Article.find_by_category(ARTICLE_CATEGORIES["News"])

and probably push some of this down into the model to unclutter your
controller.

You could also line them up in an array and use #index, but the hash
is more transparent and maintainable.

And I imagine there's a plugin somewhere that does all of this... but
the main lesson here is the hash.


David

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