From: "David A. Black" <dblack@...>
Date: 2008-05-07T20:39:25+09:00
Subject: Re: idiom for Hash like map...

Hi --

On Wed, 7 May 2008, Mikel Lindsaar wrote:

> class Fruit
>  attr_accessor :name, :price
>  def initialize(args)
>    @name = args[:name]
>    @price = args[:price]
>  end
> end
>
> array = [ Fruit.new(:name => "apple", :price => 2),
>          Fruit.new(:name => "grape", :price => 20),
>          Fruit.new(:name => "pear",  :price => 200) ]
>
> hash = Hash.new
>
> array.each do |obj|
>   hash.merge!({obj.name => obj.price})
> end
>
> hash.inspect # => "{\"grape\"=>20, \"apple\"=>2, \"pear\"=>200}"
>
>
>
> The "hash = {} / hash.merge!" thing bugs me... what is the better way?

You might like this better:

hash = Hash[*array.map {|e| [e.name, e.price] }.flatten ]

or this:

hash = array.inject({}) {|h, fruit| h[fruit.name] = fruit.price; h }


David

-- 
Rails training from David A. Black and Ruby Power and Light:
   INTRO TO RAILS         June 9-12            Berlin
   ADVANCING WITH RAILS   June 16-19           Berlin
   INTRO TO RAILS         June 24-27           London (Skills Matter)
See http://www.rubypal.com for details and updates!