Repeated import path patterns in python

Question

Is there any alternative to prevent typing repeated long paths while importing modules in python.

Current code:

from a.b.c.d.e.f.g import g1
from a.b.c.d.e.f.g import g2
from a.b.c.d.e.f.g.h import h1
from a.b.c.d.e.f.g.i import i1

I tried following code:

ref_path = a.b.c.d.e.f.g
from ref_path import g1
from ref_path import g2
from ref_path.h import h1
from ref_path.i import i1

But unfortunately it did not work. I cannot do from a.b.c.d.e.f.g import * since there might be too many modules within the ref_path.

If I am able to do this, I could easily maintain different common ref_paths used in different modules from one common location with minimal efforts.

Answer 1

There is no miracle cure for this problem.

There are, however, a few strategies you can use to make your imports a little bit nicer:

• Import all names from a module at the same time

  Instead of

  from a.b.c.d.e.f.g import g1
  from a.b.c.d.e.f.g import g2
  

  use

  from a.b.c.d.e.f.g import g1, g2
  

• Use relative imports (if you're importing within your own package)

  Assuming that this import is happening in a.b.c.d.e, you can replace

  from a.b.c.d.e.f.g.h import h1
  

  with

  from .f.g.h import h1
  

  This also works if you're in a sibling (sub-)module. For example, if this import is taking place in a.b.c.d.e.x.y, you can use

  from ...f.g.h import h1
  

  For more details about relative imports, see

  • Intra-package references
  • How to do relative imports in Python?
  • Relative imports for the billionth time

• Refactor your package (if it's your own code)

  If your package has more than 4 levels of submodules (like a.b.c.d.e), there's a pretty high chance that you should rethink your package structure. At that point you're really just shooting yourself in the foot. Perhaps c could be a standalone package, outside of a. Or perhaps e doesn't really need to be inside d and can be moved up a level or two. To quote the Zen of Python: Flat is better than nested.

Critique of other suggestions

• importlib.import_module

  Someone suggested this:

  import importlib
  ref_path = 'a.b.c.d.e.f.g'
  
  g1 = importlib.import_module(ref_path).g1
  h1 = importlib.import_module(ref_path).h.h1
  

  This serves absolutely no purpose. Now you have to write importlib.import_module(ref_path) instead of from a.b.c.d.e.f import. It's not shorter. It's not more readable. It's nothing but a more verbose version of the next suggestion. (Read on...)

• Assigning a.b.c.d.e.f to a variable

  The next suggestion was this:

  import a.b.c.d.e.f.g as ref
  
  g1 = ref.g1
  h1 = ref.h.h1
  

  This looks nice, but it doesn't always work. If the g module doesn't automatically import the h submodule, this code will throw an AttributeError. To demonstrate:

  >>> import urllib as ref
  >>> urlopen = ref.request.urlopen
  Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
  AttributeError: module 'urllib' has no attribute 'request'
  >>>
  >>> from urllib.request import urlopen  # this works, though
  >>>
  

  If this is inside your own package, there's an additional disadvantage to this solution: Your IDE most likely won't understand your imports, and won't automatically update them for you if you ever refactor your package structure. In the long run, old-fashioned import statements are more maintainable.

Answer 2

You can try to use importlib as follows:

import importlib
ref_path = 'a.b.c.d.e.f.g'

g1 = importlib.import_module(ref_path).g1
h1 = importlib.import_module(ref_path).h.h1

Edit: Another way of doing it could be to import the ref path as a package and then assigning the sub-modules to local variables as follows:

import a.b.c.d.e.f as ref

g1 = ref.g1
h1 = ref.h.h1