调试Python Prime编号程序

Question

我为Python素数生成器编写了代码,以生成前100个素数.但是,不知何故,我在输出中得到22,25等非素数.我现在一遍又一遍地重新检查了几个小时,但仍然无法弄清楚我哪里出错了......请帮忙!

这是我的代码:

from math import sqrt

y=[2]
x=3

while len(y)!=100:
   for i in range (2,int(round(sqrt(x)+1))):
     if x%i==0:
        x=x+1

     else:
        y.append(x)
        x=x+1
        break

print(y)

Answer 1

我会这样做的; 更多Pythonic:

y = [2]
x = 3
while len(y) < 100:
    if all(x % i != 0 for i in range(2, int(round(sqrt(x) + 1)))):
        y.append(x)
    x = x + 1

print(y)

该all()功能非常有用.

这与你所做的更相似; 请注意break声明及其作用:

from math import sqrt

y=[2]
x=3

while len(y) != 100:
    is_prime = True
    for i in range (2, int(round(sqrt(x) + 1))):
        if x % i == 0:
            x += 1
            is_prime = False
            break # this means that x is not prime and we can move on, note that break breaks only the for loop
    if is_prime:
        y.append(x)
        x += 1

print(y)