From: Mark Thomas <mark@...>
Date: 2008-12-19T04:47:52+09:00
Subject: Re: Show newest file in directory?

On Dec 18, 12:36 pm, Mmcolli00 Mom <mmc_coll...@yahoo.com> wrote:
> If you have a directory full of files, how can you get the newest file
> and oldest file from that directory?

One way...

  ages = Dir["C:/New"].map{|f| [f,File.mtime(f)] }.sort_by{|i|i[1]}

This gives you a sorted list of [filename,age] pairs. Then you can do
this:

  newest, oldest = ages[0][0], ages[-1][0]


Or, if you want it in one fell swoop:

  newest, oldest = Dir["C:/New"].map{|f| [f,File.mtime(f)] }.sort_by{|
i|i[1]}.map{|i| i[0]}.values_at(0,-1)

This is known as a "Swartzian Transform"

-- Mark.