Re: shuffling elements of a list

Roger Miller wrote:

DSU seems like a lot of trouble to go through in order to use an O(n
log n) sorting algorithm to do what can be done in O(N) with a few
lines of code. The core code of random.shuffle() shows how easy it is
to do it right:

for i in reversed(xrange(1, len(x))):
# pick an element in x[:i+1] with which to exchange x[i]
j = int(random() * (i+1))
x[i], x[j] = x[j], x[i]

easy to do it right? you know, the main reason for adding shuffle to the standard library was that its way too easy to get it wrong.

see e.g. this thread: http://tinyurl.com/ppgzq

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