From: w_a_x_man <w_a_x_man@...>
Date: 2011-01-09T11:10:21+09:00
Subject: Re: Best way for Array#find+transform ?

On Jan 8, 5:38 pm, "Jonas Pfenniger (zimbatm)" <jo...@pfenniger.name>
wrote:
> There is a pattern that I'm using quite regularly, but I'm not
> satisfied by my implementation.
>
> -------
> filename = "something"
> paths = ["/usr", "/usr/local", "/opt"]
> abs_file = nil
> paths.each do |path|
>   path = File.join(path, filename)
>   File.exist?(path)
>     abs_file = path
>     break
>   end
> end
> -------
>
> I know I can come up with a new method on Array that would shorten this to:
>
> ------
> abs_file = paths.find_transform do |path|
>   path = File.join(path, filename)
>   File.exist?(path) && path
> end
> ------
>
> But is there an existing method that I oversaw that does about the same ?
> 1. Stop iterating if the element is found
> 2. Return the transformed element
>
> Cheers,
>   zimbatm

filename = "something"
paths = ["/usr", "/usr/local", "/opt"]
abs_file = paths.each{|path|
  path = ( File.join( path, filename) )
  break path  if File.exist?(path)
}

If the file doesn't exist anywhere, abs_file will be equal
to the paths array.