discover path of python module [duplicate]

This question already has answers here: Closed 11 years ago.

Possible Duplicate:

Retrieving python module path

Suppose I have code in 3 python files. x.py, y.py, z.py.

x calls y and 开发者_JAVA技巧y calls z. In the code in z.py, I want to know what directory x.py is in.

Is there a function that will tell me this?

EDIT forget z.py. I just want y.py to print out the path of x.py.

EDIT

Note that the system has 30 different files all named x.py located in different directories.

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If the code in z.py has indirectly imported x.py, it will be in sys.modules. So try:

module = sys.modules.get('x')
if module is not None:
    print module.__file__

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Import x and evaluate x.__file__.

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In this circumstance those imports may lead to chain imports. So, in some functions namespace import main module.

def where_is_x():
    import __main__
    print __main__.__file__