From: Ken Allen <kallen19918@...>
Date: 2006-11-29T04:17:01+09:00
Subject: Re: rand random. You've got to be kidding

Your problem is with
@deck.sort{rand}


------------------------------------------------------------- Array#sort
     array.sort                   -> an_array                           
     array.sort {| a,b | block }  -> an_array                           
------------------------------------------------------------------------
     Returns a new array created by sorting _self_. Comparisons for the 
     sort will be done using the +<=>+ operator or using an optional    
     code block. The block implements a comparison between _a_ and _b_, 
     returning -1, 0, or +1. See also +Enumerable#sort_by+.             
                                                                        
        a = [ "d", "a", "e", "c", "b" ]                                 
        a.sort                    #=> ["a", "b", "c", "d", "e"]         
        a.sort {|x,y| y <=> x }   #=> ["e", "d", "c", "b", "a"]         

rand produces always produces values between 0 and 1 so it will always 
sort the same :)

so you need something like this

@deck.sort { if rand < 0.5 then -1; else 1; end } 
                                                         

Ken         

Smgspices@aol.com wrote:
>  
> In a message dated 11/28/2006 11:08:19 A.M. US Mountain Standard Tim,  
> brabuhr@gmail.com writes:
>
>   
>>  Surely it must be possible to initialize rand with current date and  time.
>> Documents seem to indicate this is done with rand(0) or srand  with no 
>>     
> value. I
>   
>> have tried both methods and I get the same tired old  sequence of numbers. I
>> would write my own random number generator  except I don't know how to get a
>> numeric value out of Time.
>>     
>
> Can  you post the code that isn't working for you?
>
>
>
> I was running the following in SciTE
> class Dominoes
> attr_writer :deck
> def  initialize(number)
> @deck= Array.new
> 0.upto(number)  {|i| 0.upto(i) {|j| @deck.push([i, j])}}
> end
>
> def  shuffle!
> @deck = @deck.sort{rand}
> p  @deck
> end
> end
>  
> a=Dominoes.new(6)
> a.shuffle!
>  
> The p @deck was added so I could see what was being done.
>  
> Every time I press F5 I get exactly the same result:
> [[6, 6], [4, 4], [0, 0], [5, 0], [1, 1], ...
> I get the same results if I wait a few minutes or come back the next day. I  
> get exactly the same results when I use fxri and freeRIDE. I am running Ruby  
> version 1.18.4.
>  
> Charlie
>
>