From: Farrel Lifson <farrel.lifson@...>
Date: 2007-11-21T02:12:16+09:00
Subject: Re: Quick way to get attributes (without using collect)

On 20/11/2007, Max Williams <toastkid.williams@gmail.com> wrote:
> This was inspired by Rails, but i think it's common Ruby question.  Say
> i have an array of Employee objects, which have an attribute "name".  I
> want to get all the names, as an array.
>
> Let's say i already have the variable "employees", which points to an
> array of Employee objects.
>
> What i want to do is something like this -
>
>   employee_names = employees.names
>
> But what i have to keep on doing is something like this -
>
>   employee_names = employees.collect{ |emp| emp.name}
>
> Now, this isn't a *massive* hassle, and i find Array#collect incredibly
> useful, but it's a bit annoying to have to keep typing it again and
> again.  Is there a way to set it up so that
>
> .foos
>
> is automatically treated as
>
> .collect { |x| x.foo }
>
> ?
>
> Or another way to do this simply?

You can use the Symbol#to_proc method

 class Symbol
    def to_proc
      Proc.new {|e| e.send(self)}
   end
 end

Which will let you right
 employee_names = employees.collect(&:name)

Farrel