From: Brian Adkins <lojicdotcom@...>
Date: 2007-10-14T10:55:03+09:00
Subject: Re: top 10 last played mp3's

Hmm.. it just occurred to me that many of the solutions presented here
have the flaw of potentially calling File.atime() multiple times for
the same file which would require unnecessary calls to the operating
system to get the access time of the file.

Better to compute atime only once and then sort on the result. In the
case below, I then extract the file name back out of the resulting
array, but in actuality, there may be some value in providing that to
the caller in case they could make use of the access time values.

require 'pp'
require 'find'

def n_recent_files n = 1, path = '.', exts = nil
  paths = []
  Find.find(path) do |p|
    if File.file?(p) &&
       ( exts.nil? ||
         ( (ext = File.extname(p)) &&
           !ext.empty? &&
           exts.include?(ext) ) )
      paths << [ p, File.atime(p).to_i ]
    end
  end
  paths.sort! {|a,b| b[1] <=> a[1] }[0,n].map {|x| x[0]}
end

pp n_recent_files(10, '/home/brian/temp', '.rb')
pp n_recent_files(10, '/home/brian/temp', ['.rb', '.txt'])