Managing imports within a package-CodePudding

I'm confused about how best to manage the following situation where multiple modules within a python package have the same dependencies.

Say I have a package foo whose file structure is

foo/
    __init__.py
    bar.py
    baz.py

and both bar.py and baz.py both require some other package, say external_pkg, so that they read

# foo/bar.py
import external_pkg
def bar_fn(x):
   # do something with external_pkg

and

# foo/baz.py
import external_pkg
def baz_fn(x):
   # do something with external_pkg

Question: Is there a way to refactor the package so that we can instead just include the import external_pkg line within __init__.py, rather than repeatedly writing it in the modules? Naively removing import external_pkg from the modules and placing it in __init__.py leads to NameError: name 'external_pkg' is not defined errors.

This is obviously not a big problem in the above example, but I'm trying to write a small package where there are more modules and many more common imports involved. I'm aware this might also just be a package design problem on my end. I have tried to google this, but can't seem to find the right combination of terms to get a helpful answer.

CodePudding user response：

foo/__init__.py:

import numpy as np

foo/bar.py:

from . import * # or from foo import *

print(np.zeros(10))

Running (needs to be outside the foo directory for this to work):

$ python -m foo.bar

Output:

[0. 0. 0. 0. 0. 0. 0. 0. 0. 0.]