From: Brian Candler <b.candler@...>
Date: 2008-10-31T00:00:56+09:00
Subject: Re: Sorting Array Of Dates

Josef 'Jupp' Schugt wrote:
> def datecmp(a, b, reasonable = true)
>    arra, arrb = a.split('/'), b.split('/')
>    cmp = (arra[2] <=> arrb[2])
>    return cmp if (cmp = (arra[2] <=> arrb[2])) != 0
>    if reasonable
>      (cmp = (arra[0] <=> arrb[0])) != 0 ? cmp : (arra[1] <=> arrb[1])
>    else
>      (cmp = (arra[1] <=> arrb[1])) != 0 ? cmp : (arra[0] <=> arrb[0])
>    end
> end
> 
> date = ['12/01/2007', '11/02/2007', '11/11/2005']
> puts "reasonable date format"
> puts date.sort { |a, b| datecmp(a, b) }
> puts "\nno reasonable date format"
> puts date.sort { |a, b| datecmp(a, b, false) }

I think you got "reasonable" and "unreasonable" reversed (unless you are 
American :-)

Here is a shorter solution:

MapR = lambda { |x| x.split('/').values_at(2,1,0) }
MapU = lambda { |x| x.split('/').values_at(2,0,1) }

date = ['12/01/2007', '11/02/2007', '11/11/2005']
puts "reasonable date format"
puts date.sort_by(&MapR)
puts "\nno reasonable date format"
puts date.sort_by(&MapU)
-- 
Posted via http://www.ruby-forum.com/.