Question

我正在努力定义一个全局包变量，供包中的所有模块使用。我有这段代码：

# my_module.py
from .__main__ import GLOBAL_VAR

def print_global():
    print(GLOBAL_VAR)


# __main__.py
from my_package import my_module
GLOBAL_VAR = ''

def main():
    global GLOBAL_VAR
    GLOBAL_VAR = 'myvalue'
    my_module.print_global()

if __name__ == '__main__':
    main()

我希望my_module.print_global()打印myvalue，而是打印一个空字符串（初始值）。我也尝试在GLOBAL_VAR main()声明之后导入模块，但它没有帮助。

您能否告诉我如何从GOBAL_VAR重新定义main()并使其可用于包中的所有子模块？我也接受任何其他选项，而不是使用global关键字。

编辑：建议的类似问题仅部分回答了这一问题。重新定义全局变量没有任何意义。

Answer 1

I'm not sure this is the right way to do it, but this is how I made it work:

Moved GLOBAL_VAR to a separate file settings.py to eliminate circular import, as advised by @Nearoo.
In main() redefined settings.GLOBAL_VAR the way I want.
And only then imported my_module.

Again, the problem here was that I didn't know the variable value initially and needed to define it at run time to be used by all modules.

That's how the code looks now:

# settings.py
GLOBAL_VAR = ''


# my_module.py
from .settings import GLOBAL_VAR

def print_global():
    print(GLOBAL_VAR)


# __main__.py
from my_package import settings

def main():
    settings.GLOBAL_VAR = 'myvalue'

    from my_package import my_module
    my_module.print_global()

if __name__ == '__main__':
    main()

如何在运行时更新Python中的全局包变量

1 个答案: