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copied!<p>First off, you will find all the information you need in <a href="http://docs.python.org/tutorial/modules.html" rel="noreferrer">section 6 of The Python Tutorial</a>.</p> <hr> <blockquote> <p>(1) Does python deal differently with imports on packages & modules that exist in the pythonpath than when you are trying to import from your current directory?</p> </blockquote> <p>No, it doesn't. Actually, Python always searches <code>sys.path</code> when importing modules. Modules in the current directory are only found since <code>sys.path</code> contains an entry with the empty string, meaning the current directory.</p> <hr> <blockquote> <p>(2) Why doesn't <code>import testpackage</code> give me access to <code>testpackage.testmod</code>? When I import <code>os</code>, I can then access <code>os.path</code> (etc).</p> </blockquote> <p>For efficiency, <code>import testpackage</code> only loads <code>testpackage/__init__.py</code>. If you need <code>testpackage.testmod</code>, you have to <em>explicitely</em> import it:</p> <pre><code>import testpackage # Just imports testpackage, not testpackage.testmod! import testpackage.testmod # Import *both* testpackage and testpackage.testmod! </code></pre> <p>If you always want to export <code>testmod</code>, import it within <code>__init__.py</code>, this is what <code>os</code> (<code>os/__init__.py</code>) does. This way, <code>testpackage.testmod</code> is always available implicitely if you import <code>testpackage</code>.</p> <p>Since Python is cross-platform, there is actually no way to consistently and automatically load modules in a directory, because some filesystems are case-insensitive (Windows!). Python would not know whether to load <code>os/path.py</code> as <code>os.path</code> or <code>os.Path</code>, etc.</p> <hr> <blockquote> <p>(3) With a package, should I stick to using a single <code>__init__.py</code> in the base directory, or should I be nesting them in subsequent directories?</p> </blockquote> <p>You always need an <code>__init__.py</code> for each subpackage. There were discussions on dropping this requirement, but it was decided to keep it as it is.</p> <hr> <blockquote> <p>(4) How can I import a module specifying the package name? I.E. from <code>testmod.py</code>, I would like to import <code>testpackage.testmod2</code> rather than just <code>testmod2</code>.</p> </blockquote> <p>This should work. Just ensure that you run the code from the top-level directory. If the current directory is <code>testpackage</code>, <code>testmod</code> does not know that it's in a package.</p> <p>The preferred way is to use relative intra-package imports, though:</p> <pre><code>from . import testmod2 </code></pre> <p>This prevents name clashes if there is a global module named <code>testmod2</code> and enables you to use the names of well-known modules within your package without problems.</p> <hr> <blockquote> <p>(5) What is the proper way to import submodules from the subsubs directory? The only solution I see is to append that directory to the pythonpath from <code>__init__.py</code>, but I don't know if that's the correct way.</p> </blockquote> <p>No, don't do that! Never, ever put a directory to <code>sys.path</code> when one of it's parent directories already is in <code>sys.path</code>! This could cause your modules to be loaded twice, which is a bad thing!</p> <p>Usually you should be able to load modules from subpackages using absolute or relative imports:</p> <pre><code>import testpackage.testsubs.testsubmod from testpackage.testsubs import testsubmod from .testsubs import testsubmod </code></pre> <p>Just make sure to create a <code>__init__.py</code> within <code>testsubs/</code>!</p>

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