Python:我可以在包 __init__ 模块中设置全局变量吗？

Question

所以我正在阅读 Alex Martelli 对 other question 的回答...

"One example in which I may want initialization is when at package-load time I want to read in a bunch of data once and for all (from files, a DB, or the web, say) -- in which case it's much nicer to put that reading in a private function in the package's init.py rather than have a separate "initialization module" and redundantly import that module from every single real module in the package..."

不幸的是，当我尝试这个时:

foo/__init__.py

import tables as tb
global foo
foo = tb.openFile('foo.h5', etc._)
import bar

foo/bar/__init__.py

import tables as tb
global bar
bar = foo.createGroup('/', bar)
import MyFunction`

foo/bar/MyFunction.py

def MyFunction(*of foo and bar*):
   '...'

---

>>> import foo
>>> OUTPUT= foo.bar.MyFunction.MyFunction(INPUT)
>>> bar = foo.createGroup('/', bar)
NameError: name 'foo' is not defined

如何定义全局变量而不将它们放入函数中(如 here 所示)？

Answer 1

全局变量不是全局的，因为 Python 代码的每一部分都看到相同的全局变量集。全局性实际上只是“模块范围”；模块中定义的所有变量和函数都已经是全局的，并且尽可能全局。

如果您想在另一个模块的全局变量中查看一个模块中定义的变量，唯一的方法是将第一个模块的名称导入到第二个模块中...IE:

# myModule.py
foo = "bar"

# yourModule.py
from myModule import foo