python - 为什么我的代码似乎不适用于奇数

Question

我正在尝试编写将数字分解为其素数分解的代码。到目前为止它适用于偶数，但是当我尝试奇数时它会卡住。我不知道为什么会这样。我没有收到错误，它只是停止做任何事情。

编码：

priemwaarde = 100
priemgetallen = []
nonpriemgetallen = []
for x in range(2,priemwaarde):
    prime = True
    for i in range(2,x):
        if x % i  == 0:
            prime = False
    if prime == False:
        nonpriemgetallen.append(x)
    else:
        priemgetallen.append(x)

def PriemFactoren(getal):
    factoren = []
    a = getal
    while a not in priemgetallen:
        for priem in priemgetallen:
            if a % priem == 0:
                factoren.append(priem)
                a = a / priem
    a = int(a)
    if getal not in priemgetallen:
        factoren.append(a)
    return factoren
print(PriemFactoren(56))
print(PriemFactoren(55))

Answer 1

如果在while循环中添加打印语句或调试断点，您会发现它卡住了，因为 的值a最终为 1，并且无法在priemgetallen.

打破想到的无限循环的快速解决方法是将其添加到列表中：

priemgetallen.append(1)

我想另一种选择是显式处理该值，所以这样的事情也应该打破无限循环：

def PriemFactoren(getal):
    factoren = []
    a = getal
    while a not in priemgetallen:
        #### Added lines
        if a == 1:
            break
        #### End
        for priem in priemgetallen:
            if a % priem == 0:
                factoren.append(priem)
                a = a / priem
    a = int(a)
    if getal not in priemgetallen:
        factoren.append(a)
    return factoren