Errors when importing python modules

Question

I got the following error when I compiled as followed. Why the errors? Thanks in advance.

cd /root/rel_path/ctlib/src 
python3 main_prog.py

Error:

root@Linux:~/rel_path/ctlib/src# python3 main_prog.py 
Traceback (most recent call last):
  File "main_prog.py", line 1, in <module>
    from ctlib.auto import CtAuto
ModuleNotFoundError: No module named 'ctlib'
root@Linux:~/rel_path/ctlib/src

Example path tree:

/root/rel_path/
             |--- ctlib
                     |--- src
                            |--- main_prog.py
                     |--- auto
                            |--- __init__.py

Code:

main_prog.py code:

from ctlib.auto import CtAuto

print("hello")

init.py code:

#!/usr/bin/env python3

class CtAuto:
    def print_hello(self):
        print("Hello, from CtAuto")

wuerfelfreak · Accepted Answer · 2019-08-14 09:19:09Z

1

Your import is actually looking for the CtAuto class in auto.py which does not exist in your tree:

/root/rel_path/
             |--- ctlib
                     |--- src
                            |--- main_prog.py
                     |--- auto
                            |--- __init__.py
                     |--- auto.py

Use from ctlib.auto.auto import CtAuto instead and put your CtAuto class in /root/rel_path/ctlib/auto/auto.py

[EDIT]
Because you __main__ is in a subdirecory you need to add the rootdir of the project to the Pythonpath. (before importing CtAuto)

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

or

import sys
sys.path.append('/root/rel_path/')

edited Aug 14, 2019 at 9:19

answered Aug 14, 2019 at 7:39

wuerfelfreak

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3 Comments

user1972031 Over a year ago

Still didn't work. Errors: root@Linux:~/rel_path/ctlib/src# python3 main_prog.py Traceback (most recent call last): File "main_prog.py", line 2, in <module> from ctlib.auto.auto import CtAuto ModuleNotFoundError: No module named 'ctlib' root@Linux:~/rel_path/ctlib/src#

wuerfelfreak Over a year ago

Sorry, I missread your question. Updated my Post. Now it is working for me locally.

user1972031 Over a year ago

Yes, it worked for me too. Found temporary change to PYTHONPATH environment variable is OK too: export PYTHONPATH="${PYTHONPATH}:/root/rel_path/"

Vim · Accepted Answer · 2019-08-14 09:26:23Z

1

Since you are running the program in sub-level (child) and doing import at the same level without creating any packages, which is a relative import on the same level.

Changing the main_prog.py like below will make it work.

import sys
sys.path.append("..")
from auto import CtAuto

print("hello")

answered Aug 14, 2019 at 9:26

Vim

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Errors when importing python modules

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