I investigated that scope of global variables in python is limited to the module. But I need the scope to be global among different modules. Is there such a thing? I played around __builtin__ but no luck.
thanks in advance!
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You can access global variables from other modules by importing them explicitly.
In module foo:
joe = 5
In module bar:
from foo import joe
print joe
Note that this isn't recommended, though. It's much better to hide access to a module's variables by using functions.
Eli Bendersky
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2It's even better not to store mutable state in global variables at all, but rather to use classes. – Mike Graham Feb 19 '10 at 17:31
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@Eli Bendersky, what do you mean by "It's much better to hide access to a module's variables by using functions"? @ Mike Graham, what do you mean by "use classes"? How do you do that to get what he wants? – LWZ Feb 16 '13 at 04:13
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1@LWZ: What I meant is that when a module lets other modules directly access its data, it may lead to hard-to-debug problems. If access to global data is absolutely required for some reason, at least get/set functions should be provided. These functions make it much easier to modify the code later (say, replace the global data by something else) and debug it if problems arise. – Eli Bendersky Feb 16 '13 at 13:27
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Python does not support globals shared between several modules: this is a feature. Code that implicitly modifies variables used far away is confusing and unmaintainable. The real solution is to encapsulate all state within a class and pass its instance to anything that has to modify it. This can make code clearer, more maintainable, more testable, more modular, and more expendable.
Mike Graham
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Scopes beyond the local must be written to via a reference to the scope, or after a global or nonlocal (3.x+) directive.
Ignacio Vazquez-Abrams
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