我试图在已定义的同一函数内调用一个函数

Question

我想这样做：

def enter():
    print("hi")
    enter()

但是，它首先给了我这个：

hi
hi
hi
hi
hi
hi
hi
hi
hi
hi
hi
hi
hi
hi
hi
hi
hi
hi
hi
hi
hi
hi
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hi
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hi
hi
hi
hi
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hi
hi
hi
hi
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hi
hi
hi
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hi
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hi
hi
hi
hi
hi
hi
hi
hi
hi
hi
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hi
hi
hi
hi
hi
hi
hi
hi
hi

但是，在那个数据流之后，它开始给我这样的错误：

Traceback (most recent call last):
  File "<pyshell#0>", line 1, in <module>
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter
    enter()
  File "C:/Users/offcampus/AppData/Local/Programs/Python/Python35/len finder.py", line 11, in enter

它说我已达到最大深度的递归错误，有人可以告诉我如何解决这个问题。

此外，如果有人告诉我什么递归错误甚至意味着，将不胜感激。

提前致谢！！！

Answer 1

在其内部调用函数称为递归，并且是循环的替代。但它需要付出代价。 Python需要“记住”以前对函数的所有调用，而不是每次都重置的循环。因此，您可以理解为什么最终您的计算机将耗尽内存，因为您不会停止调用enter。

这称为堆栈溢出 - 即，当计算机的“堆栈”（内存）溢出时（变得太高而且有点摔倒）。其他较老的语言，例如C，根本不能很好地处理这个问题，而堆栈溢出有点成为程序员处理的事情（这就是为什么这称为StackOverflow.com - 帮助其他人处理他们的问题）。

为了避免这种情况，Python设置了一个限制，你可以在多大程度上递归，并且通过这个限制将引发错误（而不是破坏你的计算机）。为防止代码达到此（非常高）限制，您需要指定退出条件。这是您返回而不是再次递归的地方。这可以像if语句一样简单，也可以更复杂。这也很有道理。你现在的方式，很明显为什么它一直在递归，你永远不会告诉它。