From: Paul van Delst <Paul.vanDelst@...>
Date: 2007-08-29T22:50:04+09:00
Subject: Re: Deleting empty directories

dblack@wobblini.net wrote:
> Hi --
> 
> On Wed, 29 Aug 2007, Paul van Delst wrote:
>
[snip]
>> Anyway, the need has arisen to delete empty directory heirarchies 
>> (rsync will delete the files but not the directories because of the 
>> .svn subdirs). What I've done so far is this:
>>
>>  require 'fileutils'
>>
>>  def empty_dirs
>>    @current.collect do |f|
>>      f if (File.directory?(f) && Dir.glob("#{f}/*").empty?)
>>    end.compact
>>  end
>>
>>  def remove_empty_dirs
>>    while not empty_dirs.empty?
>>      empty_dirs.each {|d| FileUtils.rm_rf(d)}
>>    end
>>  end

[snip..asking for a better way]

> You're currently using collect plus compact, but you can actually just
> use select. (That's not a general equivalence, but in this case it
> applies.)
> 
>   @current.select do |f|
>     File.directory?(f) && Dir["#{f}/*"].empty?
>   end
> 
> I'd be inclined to break things out a little. (Untested code follows
> -- please test on expendable data :-)
> 
>   require 'fileutils'
> 
>   def dirs
>     @current.select {|f| File.dir?(f) }
>   end
> 
>   def empty_dirs
>     dirs.select {|d| Dir["#{d}/*"].empty? }
>   end
> 
>   def non_empty_dirs
>     dirs - empty_dirs
>   end
> 
>   def remove_empty_dirs
>     non_empty_dirs.each {|d| FileUtils.rm_rf(d) }
>   end

Hello,

Excellent! David, thanks very much. The extra reduction of tasks is exactly what I was 
looking for (it certainly is a skill that I am having difficulty mastering).

I changed the remove_empty_dirs to a) remove the empty, not non-empty, dirs (! :o), and b) 
modify the @current file list:

   def remove_empty_dirs
     until empty_dirs.empty?
       empty_dirs.each do |d|
         @current.delete(d)
         FileUtils.rm_rf(d)
       end
     end
   end

Again, thanks very much.

cheers,

paulv