函数不改变全局变量 [英] Function Not Changing Global Variable

问题描述

我的代码如下：

my code is as follow:

done = False

def function():
    for loop:
        code
        if not comply:
            done = True  #let's say that the code enters this if-statement

while done == False:
    function()

由于某些原因，当我的代码输入if语句时，在函数完成后，不会退出while循环。

For some reason when my code enters the if statement, it doesn't exit the while loop after it's done with function().

但是，如果我这样编码：

BUT, if I code it like this:

done = False

while done == False:
    for loop:
    code
    if not comply:
        done = True  #let's say that the code enters this if-statement

... it退出while循环。这里发生了什么？

...it exits the while loop. What's going on here?

我确定我的代码输入了if语句。我还没有运行调试器，因为我的代码有很多循环（相当大的二维数组），我放弃了调试，因为它非常繁琐。在函数中，完成怎么没有被改变？

I made sure that my code enters the if-statement. I haven't run the debugger yet because my code has a lot of loops (pretty big 2D array) and I gave up on debugging due to it being so tedious. How come "done" isn't being changed when it's in a function?

推荐答案

你的问题是函数创建自己的名称空间，这意味着该函数中的 done 与第二个示例中的 done 不同。使用全局完成来使用第一个 done ，而不是创建一个新的。

Your issue is that functions create their own namespace, which means that done within the function is a different one than done in the second example. Use global done to use the first done instead of creating a new one.

def function():
    global done
    for loop:
        code
        if not comply:
            done = True

解释如何使用 global 可以找到此处

An explanation of how to use global can be found here

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