python - How to import members of all modules within a package?

Question

I am developing a package that has a file structure similar to the following:

test.py
package/
    __init__.py
    foo_module.py
    example_module.py

If I call import package in test.py, I want the package module to appear similar to this:

>>> vars(package)
mapping_proxy({foo: <function foo at 0x…}, {example: <function example at 0x…})

In other words, I want the members of all modules in package to be in package's namespace, and I do not want the modules themselves to be in the namespace. package is not a sub-package.

Let's say my files look like this:

foo_module.py:

def foo(bar):
    return bar

example_module.py:

def example(arg):
    return foo(arg)

test.py:

print(example('derp'))

How do I structure the import statements in test.py, example_module.py, and __init__.py to work from outside the package directory (i.e. test.py) and within the package itself (i.e. foo_module.py and example_module.py)? Everything I try gives Parent module '' not loaded, cannot perform relative import or ImportError: No module named 'module_name'.

Also, as a side-note (as per PEP 8): "Relative imports for intra-package imports are highly discouraged. Always use the absolute package path for all imports. Even now that PEP 328 is fully implemented in Python 2.5, its style of explicit relative imports is actively discouraged; absolute imports are more portable and usually more readable."

I am using Python 3.3.

Answer 1

I think you can get the values you need without cluttering up your namespace, by using from module import name style imports. I think these imports will work for what you are asking for:

Imports for example_module.py:

from package.foo_module import foo

Imports for __init__.py:

from package.foo_module import foo
from package.example_module import example

__all__ = [foo, example] # not strictly necessary, but makes clear what is public

Imports for test.py:

from package import example

Note that this only works if you're running test.py (or something else at the same level of the package hierarchy). Otherwise you'd need to make sure the folder containing package is in the python module search path (either by installing the package somewhere Python will look for it, or by adding the appropriate folder to sys.path).