


What's the Fastest Way to Generate a List of Prime Numbers Below N in Python?
Fastest way to list all primes below N
Can the code below be made even faster?
def get_primes(n): numbers = set(range(n, 1, -1)) primes = [] while numbers: p = numbers.pop() primes.append(p) numbers.difference_update(set(range(p*2, n+1, p))) return primes >>> timeit.Timer(stmt='get_primes.get_primes(1000000)', setup='import get_primes').timeit(1) 1.1499958793645562
Of the plain Python methods tested, **with psyco**, for n=1000000, rwh_primes1 was the fastest tested. +---------------------+-------+ | Method | ms | +---------------------+-------+ | rwh_primes1 | 43.0 | | sieveOfAtkin | 46.4 | | rwh_primes | 57.4 | | sieve_wheel_30 | 63.0 | | rwh_primes2 | 67.8 | | sieveOfEratosthenes | 147.0 | | ambi_sieve_plain | 152.0 | | sundaram3 | 194.0 | +---------------------+-------+ Of the plain Python methods tested, **without psyco**, for n=1000000, rwh_primes2 was the fastest. +---------------------+-------+ | Method | ms | +---------------------+-------+ | rwh_primes2 | 68.1 | | rwh_primes1 | 93.7 | | rwh_primes | 94.6 | | sieve_wheel_30 | 97.4 | | sieveOfEratosthenes | 178.0 | | ambi_sieve_plain | 286.0 | | sieveOfAtkin | 314.0 | | sundaram3 | 416.0 | +---------------------+-------+ Of all the methods tested, allowing numpy, for n=1000000, primesfrom2to was the fastest tested. +---------------------+-------+ | Method | ms | +---------------------+-------+ | primesfrom2to | 15.9 | | primesfrom3to | 18.4 | | ambi_sieve | 29.3 | +---------------------+-------+
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