现在是2022年，没有一个答案真的对我有用。下面是最后奏效的方法

import sys
sys.path.append('../my_class')
import my_class

我的目录结构:

src ——my_class.py 笔记本电脑 ——mynotebook.ipynb

我从mynotebook.ipynb导入my_class。

从一个恰好比当前目录高一级的目录导入模块:

from .. import module

import sys
sys.path.append("..") # Adds higher directory to python modules path.

运行python /myprogram/submodule/mymodule.py，导入/myprogram/mainmodule.py，例如via

from mainmodule import *

在Linux上(例如，在python Docker映像中)，我必须将程序根目录添加到PYTHONPATH:

export PYTHONPATH=/myprogram

@gimel's answer is correct if you can guarantee the package hierarchy he mentions. If you can't -- if your real need is as you expressed it, exclusively tied to directories and without any necessary relationship to packaging -- then you need to work on __file__ to find out the parent directory (a couple of os.path.dirname calls will do;-), then (if that directory is not already on sys.path) prepend temporarily insert said dir at the very start of sys.path, __import__, remove said dir again -- messy work indeed, but, "when you must, you must" (and Pyhon strives to never stop the programmer from doing what must be done -- just like the ISO C standard says in the "Spirit of C" section in its preface!-).

下面是一个可能对你有用的例子:

import sys
import os.path
sys.path.append(
    os.path.abspath(os.path.join(os.path.dirname(__file__), os.path.pardir)))

import module_in_parent_dir

@alex-martelli用pathlib优化的答案:

import pathlib
import sys

_parentdir = pathlib.Path(__file__).parent.parent.resolve()
sys.path.insert(0, str(_parentdir))

import module_in_parent_dir

sys.path.remove(str(_parentdir))