From: Dan Zwell <dzwell@...>
Date: 2007-08-27T06:30:33+09:00
Subject: Re: sort_by { rand } not working

Mike Dershowitz wrote:
> Hello:
> 
> I've got an array of arrays that I'd like to sort_by random.  each
> individual array is just a hash of a value and then an object.  Is there
> some reason why sort_by { rand } wouldn't work? My code is simple (teams
> is populated with a db call):
> 
>     @teams.each do |t|
>       @all << ["t",t]
>     end
>     #current not working
>     @all.sort_by { rand }
> 
> Any ideas?  Am I stretching the limit of the rand function?
> 
> Thanks!
> 
> Mike

Mike,

This has been discussed here before. Your two best choices are:
     @all = @all.sort_by {rand}
or

     for i in 0...@all.length
         j = i+rand(@all.length-i)
         @all[i], @all[j] = @all[j], @all[i]
     end

The second one will be faster, but you probably shouldn't care on small 
arrays.

Dan