On 14.04.2009, at 03:02, Michael Ash wrote:
On Mon, Apr 13, 2009 at 8:46 PM, Uli Kusterer
<witness.of.teacht...@gmx.net> wrote:
On 14.04.2009, at 02:36, Michael Ash wrote:
Note that writing a
proper shuffling algorithm is harder than it sounds. More properly,
it's easy, but figuring out whether you got the correct one or one
of
the zillions of ones that look correct but aren't is difficult.
Curious which ones look correct but aren't. Have any examples or a
link to
an article?
The most obvious one is this:
for i in 0, length(array):
swap(array[i], array[random(length(array))])
It's probably the first thing you think of when you think "shuffle an
array", but it will produce biased results.
Good point, thanks for reminding us.
Wikipedia has a decent discussion of both the proper way and why the
improper ways are improper here:
http://en.wikipedia.org/wiki/Shuffle#Shuffling_algorithms
Great!
Cheers,
-- Uli Kusterer
"The Witnesses of TeachText are everywhere..."
http://www.zathras.de
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