Python for循环:“列表索引超出范围"错误? [英] Python for loop: "list index out of range" error?

问题描述

基于Euler项目的问题3，我有一个代码:"13195的素数是5、7、13和29.600851475143数中最大的素数是多少?"

I have a code, based on problem 3 from Project Euler: "The prime factors of 13195 are 5, 7, 13 and 29. What is the largest prime factor of the number 600851475143?"

我下面有一个我认为可以使用的代码，但是第9行(for k in range(2,res[j]):)始终返回错误:"IndexError:列表索引超出范围".在遍历for循环时，似乎没有在修改列表，所以我不确定这是怎么回事.

I have a code below that I thought would work, but line 9 (for k in range(2,res[j]):) keeps returning the error: "IndexError: list index out of range". It doesn't seem like I'm modifying my list as I move through my for loop, so I'm not sure what's wrong.

def find_primes(num):
    res = []
    print(num)

    for i in range(2,num):
        if num%i==0:
            res.append(i)

    for j in res:
        for k in range(2,res[j]):
           if res[j]%k==0:
               res[j]=False
    list(filter((False).__ne__, res))

    m = max(res)
    return(m)

有人知道我要去哪里了吗?

Does anyone know where I'm going wrong?

谢谢！

推荐答案

您可能打算这样做:

for j in range(len(res)):
    for k in range(2,res[j]):

使用for j in res将遍历res个元素.

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