python - 遇到无限循环。为什么？

Question

我遇到了一个无限循环。它不断要求 social_media 输入。我试图用 if not 结束循环，当我用“enter”输入一个空白输入时，但它忽略了它。怎么会？

while True:
    if confirm_social_media == 'n':
        victims.append(victim_data)
        continue
    while True:
        social_media = input("\nType of social media: "
                             "\n'i' = Instagram"
                             "\n's' = Snapchat"
                             "\n't' = Twitter"
                             "\n'y' = Youtube"
                             "\n'f' = Facebook"
                             "\n'o' = Other"
                             "\nOr blank for next")
        if not social_media:
            break

        if social_media == 'i':
            iinput = input("Instagram " + str(inumbr) + ": ")
            if family_members == 'm':
                mother_instagram.append(iinput)
            elif family_members == 'f':
                father_instagram.append(iinput)
            elif family_members == 'o':
                other_instagram.append(iinput)

Answer 1

无限循环是由您共享代码最顶部的第一个外部 while 循环引起的。你没有什么可以打破那个循环，所以它会无限地执行内部 while 循环，即使你用你在 if not social_media: 条件中插入的 break 语句打破它，因为你没有打破外部 while 循环。

作为解决方案，只需删除顶部的 while 循环或添加另一个在代码中更改的条件，例如在您的 if not social_media: 中添加一个 bool 值，该 bool 值将用于中断您的外部while 循环:

continue_loop = True
while continue_loop :
    if confirm_social_media == 'n':
        victims.append(victim_data)
        continue
    while True:
        social_media = input("\nType of social media: "
                             "\n'i' = Instagram"
                             "\n's' = Snapchat"
                             "\n't' = Twitter"
                             "\n'y' = Youtube"
                             "\n'f' = Facebook"
                             "\n'o' = Other"
                             "\nOr blank for next")
        if not social_media:
            continue_loop = False
            break

    if social_media == 'i':
            iinput = input("Instagram " + str(inumbr) + ": ")
            if family_members == 'm':
                mother_instagram.append(iinput)
            elif family_members == 'f':
                father_instagram.append(iinput)
            elif family_members == 'o':
                other_instagram.append(iinput)

这里是关于 TutorialsPoint 中 while 循环的一些附加信息:

A while loop statement in Python programming language repeatedly executes a target statement as long as a given condition is true.

A loop becomes infinite loop if a condition never becomes FALSE. You must use caution when using while loops because of the possibility that this condition never resolves to a FALSE value. This results in a loop that never ends. Such a loop is called an infinite loop.

我建议您阅读更多有关 while 循环和 Python 的一般知识。 TutorialsPoint或 official Python documentation是开始的好地方。