python - Importing classes from different files in a subdirectory

Question

Here's the structure I'm working with:

directory/
          script.py
          subdir/
                 __init__.py
                 myclass01.py
                 myclass02.py

What I want to do is import in script.py the classes defined in myclass01.py and myclass02.py. If I do:

from subdir.myclass01 import *

It works fine for the class defined in myclass01.py. But with this solution if there are many classes defined in different files in subdir and I want to import all of them, I'd have to type one line for each file. There must be a shortcut for this. I tried:

from subdir.* import *

But it didn't work out.

EDIT: here are the contents of the files:

This is __init__.py (using __all__ as Apalala suggested):

__all__ = ['MyClass01','MyClass02']

This is myclass01.py:

class MyClass01:
    def printsomething():
        print 'hey'

This is myclass02.py:

class MyClass02:
    def printsomething():
        print 'sup'

This is script.py:

from subdir import *
MyClass01().printsomething()
MyClass02().printsomething()

This is the traceback that I get when I try to run script.py:

File "script.py", line 1, in <module>
    from subdir import *
AttributeError: 'module' object has no attribute 'MyClass01'

Answer 1

Although the names used there are different from what's shown in your question's directory structure, you could use my answer to the question titled Namespacing and classes. The __init__.py shown there would have also allowed the usepackage.py script to have been written this way (package maps to subdir in your question, and Class1 to myclass01, etc):

from package import *

print Class1
print Class2
print Class3

Revision (updated):

Oops, sorry, the code in my other answer doesn't quite do what you want — it only automatically imports the names of any package submodules. To make it also import the named attributes from each submodule requires a few more lines of code. Here's a modified version of the package's __init__.py file (which also works in Python 3.4.1):

def _import_package_files():
    """ Dynamically import all the public attributes of the python modules in this
        file's directory (the package directory) and return a list of their names.
    """
    import os
    exports = []
    globals_, locals_ = globals(), locals()
    package_path = os.path.dirname(__file__)
    package_name = os.path.basename(package_path)

    for filename in os.listdir(package_path):
        modulename, ext = os.path.splitext(filename)
        if modulename[0] != '_' and ext in ('.py', '.pyw'):
            subpackage = '{}.{}'.format(package_name, modulename) # pkg relative
            module = __import__(subpackage, globals_, locals_, [modulename])
            modict = module.__dict__
            names = (modict['__all__'] if '__all__' in modict else
                     [name for name in modict if name[0] != '_'])  # all public
            exports.extend(names)
            globals_.update((name, modict[name]) for name in names)

    return exports

if __name__ != '__main__':
    __all__ = ['__all__'] + _import_package_files()  # '__all__' in __all__

Alternatively you can put the above into a separate .py module file of its own in the package directory—such as _import_package_files.py—and use it from the package's __init__.py like this:

if __name__ != '__main__':
    from ._import_package_files import *  # defines __all__
    __all__.remove('__all__')  # prevent export (optional)

Whatever you name the file, it should be something that starts with an _ underscore character so it doesn't try to import itself recursively.