如何以编程方式设置全局（模块）变量？

I would like to define globals in a "programmatic" way. Something similar to what I want to do would be:

我想以“程序化”的方式定义全局变量。类似于我想做的事情将是：

definitions = {'a': 1, 'b': 2, 'c': 123.4}
for definition in definitions.items():
    exec("%s = %r" % definition)  # a = 1, etc.

Specifically, I want to create a module fundamentalconstants that contains variables that can be accessed as fundamentalconstants.electron_mass, etc., where all values are obtained through parsing a file (hence the need to do the assignments in a "programmatic" way).

具体来说，我想创建一个模块基本常量，其中包含可以作为fundamentalconstants.electron_mass等访问的变量，其中所有值都是通过解析文件获得的（因此需要以“编程”方式进行分配）。

Now, the exec solution above would work. But I am a little bit uneasy with it, because I'm afraid that exec is not the cleanest way to achieve the goal of setting module globals.

现在，上面的exec解决方案可行。但我对它有点不安，因为我担心exec不是实现设置模块全局变量目标的最干净的方法。

3 个解决方案

#1

You can set globals in the dictionary returned by globals():

您可以在globals（）返回的字典中设置全局变量：

definitions = {'a': 1, 'b': 2, 'c': 123.4}
for name, value in definitions.items():
    globals()[name] = value

#2

Here is a better way to do it:

这是一个更好的方法：

import sys
definitions = {'a': 1, 'b': 2, 'c': 123.4}
module = sys.modules[__name__]
for name, value in definitions.iteritems():
    setattr(module, name, value)

#3

You're right, exec is usually a bad idea and it certainly isn't needed in this case.

你是对的，exec通常是一个坏主意，在这种情况下肯定不需要。

Ned's answer is fine. Another possible way to do it if you're a module is to import yourself:

奈德的答案很好。如果你是一个模块，另一种可行的方法是自己导入：

fundamentalconstants.py:

fundamentalconstants.py：

import fundamentalconstants

fundamentalconstants.life_meaning= 42

for line in open('constants.dat'):
    name, _, value= line.partition(':')
    setattr(fundamentalconstants, name, value)

#1