【发布时间】:2020-05-17 12:47:36
【问题描述】:
我正在尝试编写一段代码,它将打印出低于给定数字的所有循环素数,但由于某种原因,我的代码打印的数字远远超出了我的限制。你觉得有什么办法可以解决吗?
from collections import deque
def gen_primes(upper):
D = {}
q = 2
while q <= upper:
if q not in D:
yield q
D[q * q] = [q]
else:
for p in D[q]:
D.setdefault(p + q, []).append(p)
del D[q]
q += 1
def next_largest(n):
k = len(str(n))
return 10**k
def circular_primes(upper):
circular = []
primes = list(gen_primes(next_largest(upper)))
for prime in primes:
string = str(prime)
digits = deque(string)
for rotation in range(1, upper):
digits.rotate(1)
if int("".join(digits)) not in primes:
break
else:
circular.append(prime)
return circular
print(circular_primes(200))
输出
[2, 3, 5, 7, 11, 13, 17, 31, 37, 71, 73, 79, 97, 113, 131, 197, 199, 311, 337, 373, 719, 733, 919,
971, 991]
【问题讨论】:
-
您将
next_largest定义为 10**3 == 1000,因此您可以得到所有素数直到 1000