From: Chuck Remes <cremes.devlist@...>
Date: 2009-08-31T04:38:14+09:00
Subject: Re: Sorting an array by multiple elements?


On Aug 30, 2009, at 2:05 PM, Paul Carvalho wrote:

> Got it!
>
>> The sort with the sample data above works as I expect, but for some
>> reason it still isn't sorting correctly with my real data.  I'll keep
>> looking at it.  I must be missing something else, although I can't
>> think what it might be right now.
>>
>
> The 'name' element turned out to be an array. (Doh!) I flattened the
> data and the sort_by now works correctly, as expected.
>
> Thanks again for all your help.

Be advised that sort_by sorts in ascending order by default. If you  
want to sort descending, things get a little complicated. For example,  
you can sort descending by putting a minus (-) sign in front of your  
Fixnum variables. That works nicely. Now try to do that with a string.  
Kaboom.

Try this code to make it (mostly) work.

# Added to the String class so in Enumerable#sort_by we can
# use the #- to reverse the sort order from ascending to descending
# Not perfect; see ruby-talk ML 20090320 where it shows that it doesn't
# always work correctly
class String
   def -@
     self.gsub(/./) {|s| (255 - s[0]).chr }
   end
end

cr