如何使局部变量(在函数内部)成为全局变量 [英] How to make a local variable (inside a function) global

问题描述

可能重复:
在函数中使用全局变量除了创建它们的那个

Possible Duplicate:
Using global variables in a function other than the one that created them

我正在使用函数，以便我的程序不会一团糟，但我不知道如何将局部变量变成全局变量.

I'm using functions so that my program won't be a mess but I don't know how to make a local variable into global.

推荐答案

这里有两种方法可以实现相同的目的:

Here are two methods to achieve the same thing:

使用参数并返回(推荐)

def other_function(parameter):
    return parameter + 5

def main_function():
    x = 10
    print x    
    x = other_function(x)
    print x

运行main_function时，将获得以下输出

When you run main_function, you'll get the following output

>>> 10
>>> 15

使用全局变量(从不这样做)

x = 0   # The initial value of x, with global scope

def other_function():
    global x
    x = x + 5

def main_function():
    print x    # Just printing - no need to declare global yet
    global x   # So we can change the global x
    x = 10
    print x
    other_function()
    print x

现在您将获得:

>>> 0    # Initial global value
>>> 10   # Now we've set it to 10 in `main_function()`
>>> 15   # Now we've added 5 in `other_function()`

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