[Python-Dev] a note in random.shuffle.__doc__ ...

Greg Ewing greg.ewing at canterbury.ac.nz
Sun Jun 11 02:39:42 CEST 2006

Terry Jones wrote:
> That doc note should surely be removed.  Perhaps it's an artifact from some
> earlier shuffle algorithm.
> The current algorithm (which is simple, well known, and which produces all
> permutations with equal probability) only calls the RNG len(x) - 1 times.

It's not a matter of how many times it's called, but
of how much internal state it has.

A generator with only N possible internal states can't
possibly result in more than N different outcomes from
any algorithm that uses its results.


More information about the Python-Dev mailing list