Sorting question, at rest

DunbarX at aol.com DunbarX at aol.com
Thu Feb 11 17:45:01 EST 2010


Peter.

I think I now see the difference when a random sortkey is used to 
randomize, as opposed to simply creating a random list from data:

put "1,2,3" into temp
repeat 100
   put item random(3) of temp & return after myList --works well
end repeat

is very different than:

put "1,2,3" into temp
repeat 100
   sort items of temp by random(3)
   put temp & return after myList -- hardly works at all
end repeat

I saw them as similar. I was wrong.

Craig Newman



In a message dated 2/11/10 11:23:00 AM, pmbrig at gmail.com writes:

> Brian Yennie gave the explanation. When you use random(3) as a sort 
> key you have a high chance (in fact I think it's 50%) that two of the 
> items will be assigned the same sort key, and thus their relative 
> position will be preserved, giving a decidedly non-random sort. If you 
> sort by random(1000000) or some suitably high number the chances of 
> getting the same sortkey in your three iterations is miniscule.
> 



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