Python项目结构，项目主文件导入助手

Question

这是我的项目结构。

[~/Sandbox/pystructure]:$ tree
.
├── pystructure
│   ├── __init__.py
│   ├── pystructure.py
│   └── utils
│       ├── eggs
│       │   ├── base.py
│       │   └── __init__.py
│       ├── __init__.py
│       └── spam.py
├── README.md
└── requirements.txt

3 directories, 8 files

这些是文件的内容，

[~/Sandbox/pystructure]:$ cat pystructure/utils/spam.py 
def do():
    print('hello world (from spam)!')

[~/Sandbox/pystructure]:$ cat pystructure/utils/eggs/base.py 
def do():
    print('hello world (from eggs)!')

[~/Sandbox/pystructure]:$ cat pystructure/utils/eggs/__init__.py 
from .base import do

[~/Sandbox/pystructure]:$ cat pystructure/pystructure.py 
#!/usr/bin/python3

from .utils import spam, eggs

def main():
    spam.do()
    eggs.do()

if __name__ == '__main__':
    main()

但是，当我尝试像这样运行应用程序时，出现此错误，

[~/Sandbox/pystructure]:$ python3 pystructure/pystructure.py 
Traceback (most recent call last):
  File "pystructure/pystructure.py", line 3, in <module>
    from .utils import spam, eggs
ModuleNotFoundError: No module named '__main__.utils'; '__main__' is not a package

或者当我尝试从创建文件的目录中运行代码时(这不是我的愿望，因为我想将它作为服务运行或使用 cron)，

[~/Sandbox/pystructure]:$ cd pystructure/

[~/Sandbox/pystructure/pystructure]:$ python3 pystructure.py 
Traceback (most recent call last):
  File "pystructure.py", line 3, in <module>
    from .utils import spam, eggs
ModuleNotFoundError: No module named '__main__.utils'; '__main__' is not a package

但是如果我导入它，它确实有效(但是只能从基本目录...)

[~/Sandbox/pystructure/pystructure]:$ cd ..

[~/Sandbox/pystructure]:$ python3
Python 3.6.7 (default, Oct 22 2018, 11:32:17) 
[GCC 8.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from pystructure import pystructure
>>> pystructure.main()
hello world (from spam)!
hello world (from eggs)!
>>> 

(如果我尝试从它所在的目录导入它，我会收到此错误)，

[~/Sandbox/pystructure]:$ cd pystructure/

[~/Sandbox/pystructure/pystructure]:$ python3
Python 3.6.7 (default, Oct 22 2018, 11:32:17) 
[GCC 8.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import pystructure
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "~/Sandbox/pystructure/pystructure/pystructure.py", line 3, in <module>
    from .utils import spam, eggs
ImportError: attempted relative import with no known parent package
>>> 

我认为我的问题来自于对 PYTHONPATH 没有完全的理解，我尝试了谷歌搜索，但我还没有找到我的答案......请提供任何见解。

Answer 1

当您从包中导入时，您是从该包的 __init__.py 中导入....

所以在您的 utils 包中，您的 __init__.py 是空的。

尝试将此添加到您的 utils/__init__.py

print("utils/__init__.py")
from . import eggs
from . import spam

现在，当你说 from utils import eggs, spam 时，你是说，从 utils 包的 init.py 导入我在那里导入的东西.

此外，在 pystructure.py

改变这个

from .utils import  eggs, spam 

进入这个

from utils import  eggs, spam