当我在 sys.path 中有包时，在 python 中显示导入错误答案

【问题标题】：showing import error in python while i have the packages in sys.path当我在 sys.path 中有包时，在 python 中显示导入错误
【发布时间】：2020-08-17 14:03:45
【问题描述】：

我在 sys.path 上有包，但它显示导入错误。但是如果我尝试在目录结构的上层导入相同的包，它就可以工作。

(flask) [ tests ] $ python3
Python 3.7.5 (default, Nov 20 2019, 09:21:52) 
[GCC 9.2.1 20191008] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> sys.path
['', '/usr/lib/python37.zip', '/usr/lib/python3.7', '/usr/lib/python3.7/lib-dynload', '/home/rohit/flask/lib/python3.7/site-packages', '/home/rohit/flask/src/flaskr', '/home/rohit/flask/src/mycode']
>>> import mycode
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'mycode'
>>> import flaskr
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'flaskr'
>>> exit()


(flask) [ tests ] $ cd ..
(flask) [ src ] $ python3
Python 3.7.5 (default, Nov 20 2019, 09:21:52) 
[GCC 9.2.1 20191008] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> sys.path
['', '/usr/lib/python37.zip', '/usr/lib/python3.7', '/usr/lib/python3.7/lib-dynload', '/home/rohit/flask/lib/python3.7/site-packages', '/home/rohit/flask/src/flaskr', '/home/rohit/flask/src/mycode']
>>> import mycode
>>> import flaskr
>>>

【问题讨论】：

标签： python python-3.x flask import

【解决方案1】：

如您的测试所示：如果您要导入的包是/home/rohit/flask/src/flaskr 和/home/rohit/flask/src/mycode，则需要将/home/rohit/flask/src 添加到您的路径中。您的第二次尝试有效，因为您在此文件夹中。

你可以进一步测试它：

import sys
sys.path.append('/home/rohit/flask/src')
# with relative import for a test module in test subdirectory:
# sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

import mycode
import flaskr

来源：https://docs.python.org/3.7/tutorial/modules.html#packages：When importing the package, Python searches through the directories on sys.path looking for the package subdirectory.

【讨论】：