Python3相对进口

Question

I'm tired of reading one-off use cases of relative imports so I figured I'd as a question to get an example of how to do a relative import from a directory above and bellow , for both importing module functions and class objects.

directory structure:

.
├── lib
│   ├── __init__.py
│   └── bar.py
└── src
    ├── main.py
    └── srclib
        ├── __init__.py
        └── foo.py

bar.py

def BarFunc():
        print("src Bar function")

class BarClass():
        def __inti__(self):
                print("src Bar Class")
        def test(self):
                print("BarClass working")

foo.py

def FooFunction():
        print("srclib Foo function")

class FooClass():
        def __init__(self):
                print("srclib Foo Class")
        def test(self):
                print("FooClass working")

Question: What is the syntax in python 3 to import for these use cases?

main.py

# What is the syntax to import in python 3?

# I want to be able to call FooFunc()
foo.FooFunc()

# I want to be able to create a FooClass() object
foo_class = foo.FooClass()
foo_class.test()

# I want to be able to call FooFunc()
bar.BarFunc()

# I want to be able to create a BarClass() object
bar_class = bar.BarClass()
bar_class.test()

Answer 1

It all depends on where you start your python interpreter from. In your case, I would suggest you to start the interpreter from your project's root directory while making the following changes:

In file src/srclib/__init__.py add:

from . import foo

The reason for doing this is to explicitly state in your __init__.py file what to import from your module.

In your main.py file, add the following:

from lib import bar
from src.srclib import foo

Hope this helps!