From: Rob Biedenharn <Rob@...>
Date: 2009-03-20T12:01:42+09:00
Subject: Re: Complex sort of matrix possible, e.g. like Excel?

On Mar 19, 2009, at 10:44 PM, Ryan Davis wrote:
> On Mar 17, 2009, at 22:02 , RichardOnRails wrote:
>
>> I've got an array of rows (and thus a matrix) created user FasterCSV
>> to extract data from a CSV file.  I'd like to sort the matrix on
>> column A ascending and, within that, column B descending.  I looked  
>> at
>> Matrix,  but it doesn't seem to address that functionality.  Is there
>> a package that does, or do I have to write my own SuperMatrix
>> inherited from Matrix?
>
> I'm kinda surprised nobody has said this:
>
>    sorted = matrix.sort_by { |row| [row[0], -row[1]] }
>
> P.S. PLEASE trim to the relevant parts when you reply. In some of  
> your email on this thread you have two whole copies of nearly the  
> whole thread.


Actually, it was suggested, but it assumes that row[1] has a -@  
method.  The OP confirmed later that the columns are text, not numbers.

-Rob

Rob Biedenharn		http://agileconsultingllc.com
Rob@AgileConsultingLLC.com