What is the correct way to use Python import to import a name from a submodule?
I’m trying to replicate the behavior of from foo.bar import object using the __import__ function, but I seem to be encountering issues.
For simpler cases, like from glob import glob, it’s straightforward:
glob = __import__("glob").glob
However, the problem arises when I’m trying to import a name from a subpackage (e.g., from foo.bar import object). I want to do something like:
string_to_import = "bar"
object = __import__("foo." + string_to_import).object
But this only imports the top-level foo package, not the foo.bar subpackage:
__import__("foo.bar")
<module 'foo' from 'foo/__init__.pyc'>
How can I use Python import to correctly import a name from a submodule or subpackage?
From my experience working with dynamic imports, I’d say that the Python __import__ function will return the top-level module of a package unless you provide a non-empty fromlist argument. To import a specific name from a submodule, you can pass fromlist=['object']. This helps you access the submodule and the specific object you need. For example:
_temp = __import__('foo.bar', fromlist=['object'])
object = _temp.object
By doing this, foo.bar gets properly loaded, and the object becomes available. It’s essential to refer to the Python documentation on python __import__ for deeper insights and usage details. You’ll see what I mean once you get into the nuances.
That’s a solid way to approach it, @jacqueline-bosco! I personally prefer using getattr along with __import__ for even more flexibility. This method allows you to dynamically retrieve an object from an imported module. Here’s how I would do it:
module = __import__('foo.bar', fromlist=['object'])
object = getattr(module, 'object')
getattr retrieves the object dynamically, so it’s great when you’re not sure exactly what attribute you need ahead of time or want to make your code more adaptable. Again, the python __import__ function plays a key role here for handling imports, but using getattr really gives you more control over the process.
You know, after working with both methods, I’ve found that importlib is an even more flexible way to dynamically load submodules. It’s a cleaner approach and is the recommended method moving forward. Here’s how you can handle it with importlib:
import importlib
module = importlib.import_module('foo.bar')
object = getattr(module, 'object')
This method doesn’t rely on the older python __import__ function, and it makes handling dynamic imports cleaner and more manageable. Plus, it’s easier to manage dependencies this way, especially as your project grows. Importlib’s got your back when it comes to modern Python imports!