From: Robert Klemme <shortcutter@...>
Date: 2009-11-02T17:31:00+09:00
Subject: Re: mtime.max

2009/11/2 Derek Smith <derekbellnersmith@yahoo.com>:
>> Why do you convert the mtime (a Time object) to an integer? Time
>> objects are comparable. Try to omit the ".to_i" and compare the
>> Time objects that represent the mtimes.

> I feel like Im smoking crack and getting pissed off at the same time! No
> offence intended!
> This is still not working as I should be seeing
> /backups/prod_db_bkup_Thr2009-10-291052.gz
> as the oldest file.
>
>
>  require 'time'
>    stats = Hash.new
>    DB_BKUP1.each do |dbfile|
>        stats[dbfile] = [File.stat(dbfile).mtime]
>    end
>
>    stats_sorted = Hash.new
>    stats_sorted = stats.sort { |x,y| x[1]<=>y[1] }
>
>    oldest = stats_sorted[0][1].first
>    p oldest
>    oldestfile = ''
>    stats.each_value do |v|
>        if  #{v} < #{oldest}
>            oldest = v
>            oldestfile = stats.index(oldest)
>        end
>    end
>    puts oldestfile
>    puts "exit"
>    exit
> end
>
> prod_DB_OS_bkup.rb: 108 lines, 2997 characters.
> [root@.../usr/local/vrep/OS_scripts]# ruby prod_DB_OS_bkup.rb
> Thu Oct 29 10:52:41 -0400 2009
> /backups/prod_db_bkup_Thr2009-10-291054.gz
> exit
>
> [root@.../usr/local/vrep/OS_scripts]# ls -alrt /backups/prod*.gz
> -rw-r--r--  1 root  wheel  38608780 Oct 29 10:52
> /backups/prod_db_bkup_Thr2009-10-291052.gz
> -rw-r--r--  1 root  wheel  38608793 Oct 29 10:54
> /backups/prod_db_bkup_Thr2009-10-291054.gz
> -rw-r--r--  1 root  wheel  38608802 Oct 29 11:00
> /backups/prod_db_bkup_Thr2009-10-29110.gz
> -rw-r--r--  1 root  wheel  38609193 Oct 30 10:42
> /backups/prod_db_bkup_Fri2009-10-301042.gz
> -rw-r--r--  1 root  wheel  38770872 Nov  1 16:29
> /backups/prod_db_bkup_Sun2009-11-011629.gz

IMHO you're making your life too difficult: for the youngest file you
can use Enumerable#max_by:

09:25:28 Temp$ ls -lt | head -5
total 339
-rwx------+ 1 RKlemme Domain Users   1544 Nov  2 09:25
etilqs_y5Wb4Ntehb25BGev1S84-journal*
-rwx------+ 1 RKlemme Domain Users 184862 Nov  2 09:14 xphoon.bmp*
drwx------+ 2 RKlemme Domain Users      0 Nov  2 09:14 notes6030C8/
drwxr-xr-x+ 2 RKlemme Domain Users      0 Nov  2 09:11 hsperfdata_rklemme/
09:26:07 Temp$ allruby -e 'puts Dir["*"].max_by {|f| File.mtime f}'
CYGWIN_NT-5.1 padrklemme1 1.5.25(0.156/4/2) 2008-06-12 19:34 i686 Cygwin
========================================
ruby 1.8.7 (2008-08-11 patchlevel 72) [i386-cygwin]
etilqs_y5Wb4Ntehb25BGev1S84-journal
========================================
ruby 1.9.1p129 (2009-05-12 revision 23412) [i386-cygwin]
etilqs_y5Wb4Ntehb25BGev1S84-journal


For the oldest it is Enumerable#min_by:

09:26:41 Temp$ ls -lt | tail -5
-rwx------+ 1 RKlemme Domain Users    663 Feb  6  2009 to_h.rb*
-rwxr--r--  1 RKlemme Domain Users    548 Jan 27  2009 typo-finder.rb*
-rwx------+ 1 RKlemme Domain Users    390 Jan 20  2009 req.rb*
-rwx------+ 1 RKlemme Domain Users    426 Dec 11  2008 ds.rb*
-rwx------+ 1 RKlemme Domain Users    787 Dec  9  2008 drb-demo.rb*
09:26:47 Temp$ allruby -e 'puts Dir["*"].min_by {|f| File.mtime f}'
CYGWIN_NT-5.1 padrklemme1 1.5.25(0.156/4/2) 2008-06-12 19:34 i686 Cygwin
========================================
ruby 1.8.7 (2008-08-11 patchlevel 72) [i386-cygwin]
drb-demo.rb
========================================
ruby 1.9.1p129 (2009-05-12 revision 23412) [i386-cygwin]
drb-demo.rb

Even if you want the whole array sorted by mtime you can use #sort_by
and #last or #first:

09:26:53 Temp$ allruby -e 'ar = Dir["*"].sort_by {|f| File.mtime f};
puts ar.first, ar.last'
CYGWIN_NT-5.1 padrklemme1 1.5.25(0.156/4/2) 2008-06-12 19:34 i686 Cygwin
========================================
ruby 1.8.7 (2008-08-11 patchlevel 72) [i386-cygwin]
drb-demo.rb
etilqs_y5Wb4Ntehb25BGev1S84-journal
========================================
ruby 1.9.1p129 (2009-05-12 revision 23412) [i386-cygwin]
drb-demo.rb
etilqs_y5Wb4Ntehb25BGev1S84-journal


Kind regards

robert


-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/