[David Mertz]

Oops... yeah. I had fixed the "up to and including" previously, but somehow I copied the wrong version to the thread.

Doesn't matter ;-) The point here, to me, is that the prime generator I pointed at is significantly faster, more memory-frugal, and even "more correct", than even experienced Python programmers are likely to come up with at first.

That gives it real value as a candidate for a standard library. But something much fancier than that? I don't think so, for reasons already given - the code is still understandable for non-experts if they give it some effort. Fancier stuff may not be.

For example, in my own code I use a fancier version of that incorporating a wheel sieve too, and even the _setup_ function for that is harder to understand all on its own:

That gives it real value as a candidate for a standard library. But something much fancier than that? I don't think so, for reasons already given - the code is still understandable for non-experts if they give it some effort. Fancier stuff may not be.

For example, in my own code I use a fancier version of that incorporating a wheel sieve too, and even the _setup_ function for that is harder to understand all on its own:

def _setup_sieve(ps, show=True):

from math import gcd

assert ps[0] == 2

prod = totient = 1

for p in ps:

assert pp(p)

prod *= p

totient *= p-1

if show:

print("ps", ps, "prod", prod)

mod2i = [None] * prod

mod2i[1] = 0

deltas = []

last = 1

for i in range(3, prod, 2):

if gcd(prod, i) == 1:

deltas.append(i - last)

mod2i[i] = len(deltas)

last = i

deltas.append(2) # wrap around from prod-1 to 1

assert len(deltas) == totient

assert sum(deltas) == prod

if show:

print("deltas", deltas, len(deltas))

print("mod2i", mod2i)

return ps, deltas * 2, mod2i

_siv_glob = _setup_sieve([2, 3, 5, 7], show=False)

I don't want that in the standard library - and twice as much don't want it if somebody else wrote it ;-)