[Python-Dev] a note in random.shuffle.doc ... (original) (raw)

Tim Peters tim.peters at gmail.com
Mon Jun 12 05:25:53 CEST 2006

[Terry Jones]

The code below uses a RNG with period 5, is deterministic, and has one initial state. It produces 20 different outcomes.

Well, I'd call the sequence of 20 numbers it produces one outcome.

From that view, there are at most 5 outcomes it can produce (at most 5 distinct 20-number sequences). In much the same way, there are at most P distinct infinite sequences this can produce, if the PRNG used by random.random() has period P:

def belch(): import random, math start = random.random() i = 0 while True: i += 1 yield math.fmod(i * start, 1.0)

The trick is to define "outcome" in such a way that the original claim is true :-)

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