Loading all modules in a folder in Python

Question

Could someone provide me with a good way of importing a whole directory of modules?
I have a structure like this:

/Foo
    bar.py
    spam.py
    eggs.py

I tried just converting it to a package by adding __init__.py and doing from Foo import * but it didn't work the way I had hoped.

Answer 1

Add the __all__ Variable to __init__.py containing:

__all__ = ["bar", "spam", "eggs"]

See also http://docs.python.org/tutorial/modules.html

Answer 2

See that your __init__.py defines __all__. The modules - packages doc says

The __init__.py files are required to make Python treat the directories as containing packages; this is done to prevent directories with a common name, such as string, from unintentionally hiding valid modules that occur later on the module search path. In the simplest case, __init__.py can just be an empty file, but it can also execute initialization code for the package or set the __all__ variable, described later.

...

The only solution is for the package author to provide an explicit index of the package. The import statement uses the following convention: if a package’s __init__.py code defines a list named __all__, it is taken to be the list of module names that should be imported when from package import * is encountered. It is up to the package author to keep this list up-to-date when a new version of the package is released. Package authors may also decide not to support it, if they don’t see a use for importing * from their package. For example, the file sounds/effects/__init__.py could contain the following code:

__all__ = ["echo", "surround", "reverse"]

This would mean that from sound.effects import * would import the three named submodules of the sound package.

Answer 3

iterate thru all *.py files and put them as all , but i am curious why you need that, there MUST be a better way.

here is a hacky way

import os
import glob
__all__ = [ os.path.basename(f)[:-3] for f in glob.glob(os.path.dirname(__file__)+"/*.py")]

Answer 4

Make the Foo directory a package by adding an __init__.py. In that __init__.py add:

import bar
import eggs
import spam

Since you want it dynamic (which may or may not be a good idea), list all py-files with list dir and import them with something like this:

import os
for module in os.listdir(os.path.dirname(__file__)):
    if module == '__init__.py' or module[-3:] != '.py':
        continue
    __import__(module[:-3], locals(), globals())
del module

Then, from your code do this:

import Foo

You can now access the modules with

Foo.bar
Foo.eggs
Foo.spam

etc. from Foo import * is not a good idea for several reasons, including name clashes and making it hard to analyze the code.