如何解决：尝试在没有已知父 package 的情况下进行相对导入

Question

I have a project structure with mostly empty python files:

-project
  --work1
      --__init__.py
      --app.py
      --momo.py

momo.py

import numpy as np
def plus(x):
    return x

app.py

from . import momo
a = momo.plus(6)

Running app.py directly results in this error:

from . import momo
ImportError: attempted relative import with no known parent package

I have tried change to "from plus import momo" but this yields the same error.

Python version 3.8

Any hints would be much appreciated.

Answer 1

You shouldn't import like you said.

you can just try this:

import momo

it should add momo to your current file.

and for using functions which has been declared in momo , you should call the function name after momo. . for example:

a = momo.plus(12)

if you just want to import plus`` from momo``` file, you can try

from momo import plus

then you just need to call function name, instead of the whole file and functions together. eg:

a = plus(12)

Answer 2

Try running it from project directory as module (-m flag):

$ cd project
$ python -m work1.app 

because when you're starting app directly like python app.py , is doesn't know that current folder is actually a package with __init__.py but dot in from. import * from. import * is a shortcut for a current package.