From c5a37622868919d3af2d4d3011df7bfe6eebc689 Mon Sep 17 00:00:00 2001 From: Walt Mankowski Date: Mon, 4 Jul 2022 18:50:27 -0400 Subject: python code to find primes --- challenge-172/walt-mankowski/python/primes.py | 15 +++++++++++++++ 1 file changed, 15 insertions(+) create mode 100644 challenge-172/walt-mankowski/python/primes.py (limited to 'challenge-172/walt-mankowski/python/primes.py') diff --git a/challenge-172/walt-mankowski/python/primes.py b/challenge-172/walt-mankowski/python/primes.py new file mode 100644 index 0000000000..686143de0f --- /dev/null +++ b/challenge-172/walt-mankowski/python/primes.py @@ -0,0 +1,15 @@ +from math import sqrt + +# find the primes up to n using the sieve of Eratosthenes and return +# them as list +def primes_to(n): + is_prime = [True] * (n+1) + is_prime[0] = is_prime[1] = False + for i in range(2, int(sqrt(n))+1): + if is_prime[i]: + for j in range(i+i, n+1, i): + is_prime[j] = False + + return [i for i,val in enumerate(is_prime) if val] + + -- cgit