From: Michael Gaunnac <mlgaunnac@...>
Date: 2004-10-09T00:55:14+09:00
Subject: Re: A sort_by descending sort

gabriele renzi wrote:
> Michael Gaunnac ha scritto:
>
>> Perhaps this has already been covered, but I discovered this idiom
>> for doing a descending sort using sort_by.
>
> why not:
>  >> [1,2.0,6,23 ,546,421.1,,0.1].sort_by {|x| 1-x}
> => [546, 421.1, 23, 6, 2.0, 1, 0.1]
>
> Anyway, thankx for making me think of this :)

More context:

arr = %W{
A10/04/200420:30
A10/04/200405:00
A10/04/200420:00
A10/06/200405:00
A10/07/200409:37
A10/07/200419:00
A10/07/200421:30
E10/08/200404:00
A10/08/200407:50
A10/08/200405:15
D10/08/200404:00
A10/08/200305:00
A10/08/200405:00
A10/08/200403:55
B10/08/200404:15
A10/07/200419:30
A10/07/200422:00
B10/07/200405:00
B10/08/200407:50
A10/08/200407:50
A10/08/200407:25
C10/08/200404:00
B10/08/200404:00
A10/08/200404:45
A10/08/200404:10
B10/08/200404:10
A10/08/200404:00
       }
# sort                         ascending      descending  year
descending  month/day                          descending hour:minute
arr = arr.sort_by {|i| [[i.slice(0,1)],
[i.slice(7,4).tr('0-9','9876543210')],
[i.slice(1,5).tr('/0-9','/9876543210')],
[i.slice(11,5).tr(':0-9',':9876543210')]]}

arr.each {|i| print i, "\n"}


<challenge>
Can this sort be simplified (with Ruby of course)?
</challenge>