Structure:
|--folder/
|--a.py
|--main.py
When loading module 'main' into module 'a'
#a.py
import main
the following error occurs - ModuleNotFoundError: No module named 'main'.
PyCharm copes with this task, but VSCode does not. What's the matter?
Looking at your directory structure, I presume that a.py and main.py are in different directories. If that is the case, then the answers to [this question][1] should be useful. To elaborate a bit further, you can use the sys module to specify the path to the other module (main.py) i.e. if main.py is in a different directory from a.py.
import sys
sys.path.append('/path_to_main_module_directory/')
import main
print("This import is for the main module")
I hope this helps!
[1]: Importing files from different folder
what is this error please help me iam getting it in python & iam new ? iam using the open source code of simso simulator
ModuleNotFoundError: No module named 'main.MetricsWindow'; 'main' is not a package
This error: ModuleNotFoundError: No module named '__main__.MetricsWindow'; '__main__' is not a package may also occur if you have named the main program file you created as __main__.py and try to run it as python __main__.py or another file has the name __main__.py in the same folder from which you run your program. Python will consider your program file as a module and try to find something in it that is naturally not in it. About where Python is looking for modules, see sys.path.
In this case, rename your program file so that its name does not equal with the name of the imported module.
When I build the linux image with buildroot, I have enable the python3 and python zlib in the config like below:
BR2_PACKAGE_OPENCV3=y
BR2_PACKAGE_OPENCV3_LIB_PYTHON=y
BR2_PACKAGE_OPENCV3_LIB_IMGCODECS=y
BR2_PACKAGE_OPENCV3_LIB_IMGPROC=y
BR2_PACKAGE_OPENCV3_WITH_JPEG=y
BR2_PACKAGE_PYTHON3_ZLIB=y
Build is ok, and I can enter into python3, but the error "ModuleNotFoundError: No module named 'zlib' always happened when I import some package.
anyone know how to rolve it.
thanks.
Whenever I run this script under the folder app/klarna_basic/klarna_basic_test.py, I always get the error:
ModuleNotFoundError: No module named 'app'.
The code used for importing is,
from app.Fortnox import Fortnox
Fortnox.py is located in app(app/Fortnox.py) folder.
See the image below.
What seems to be problem on this one?
it looks like Fortnox.py is inside the subfolder klarna_basic
from klarna_basic.Fortnox import Fortnox
orimport klarna_basic.Fortnox
Currently trying to work in Python3 and use absolute imports to import one module into another but I get the error ModuleNotFoundError: No module named '__main__.moduleB'; '__main__' is not a package. Consider this project structure:
proj
__init__.py3 (empty)
moduleA.py3
moduleB.py3
moduleA.py3
from .moduleB import ModuleB
ModuleB.hello()
moduleB.py3
class ModuleB:
def hello():
print("hello world")
Then running python3 moduleA.py3 gives the error. What needs to be changed here?
.moduleB is a relative import. Relative only works when the parent module is imported or loaded first. That means you need to have proj imported somewhere in your current runtime environment. When you are are using command python3 moduleA.py3, it is getting no chance to import parent module. You can:
from proj.moduleB import moduleB OR
You can create another script, let's say run.py, to invoke from proj import moduleA
Good luck with your journey to the awesome land of Python.
Foreword
I'm developing a project which in fact is a Python package that can be installed through pip, but it also exposes a command line interface. I don't have problems running my project after installing it with pip install ., but hey, who does this every time after changing something in one of the project files? I needed to run the whole thing through simple python mypackage/main.py.
/my-project
- README.md
- setup.py
/mypackage
- __init__.py
- main.py
- common.py
The different faces of the same problem
I tried importing a few functions in main.py from my common.py module. I tried different configurations that gave different errors, and I want to share with you with my observations and leave a quick note for future me as well.
Relative import
The first what I tried was a relative import:
from .common import my_func
I ran my application with simple: python mypackage/main.py. Unfortunately this gave the following error:
ModuleNotFoundError: No module named '__main__.common'; '__main__' is not a package
The cause of this problem is that the main.py was executed directly by python command, thus becoming the main module named __main__. If we connect this information with the relative import we used, we get what we have in the error message: __main__.common. This is explained in the Python documentation:
Note that relative imports are based on the name of the current module. Since the name of the main module is always __main__, modules intended for use as the main module of a Python application must always use absolute imports.
When I installed my package with pip install . and then ran it, it worked perfectly fine. I was also able to import mypackage.main module in a Python console. So it looks like there's a problem only with running it directly.
Absolute import
Let's follow the advise from the documentation and change the import statement to something different:
from common import my_func
If we now try to run this as before: python mypackage/main.py, then it works as expected! But, there's a caveat when you, like me, develop something that need to work as a standalone command line tool after installing it with pip. I installed my package with pip install . and then tried to run it...
ModuleNotFoundError: No module named 'common'
What's worse, when I opened a Python console, and tried to import the main module manually (import mypackage.main), then I got the same error as above. The reason for that is simple: common is no longer a relative import, so Python tries to find it in installed packages. We don't have such package, that's why it fails.
The solution with an absolute import works well only when you create a typical Python app that is executed with a python command.
Import with a package name
There is also a third possibility to import the common module:
from mypackage.common import my_func
This is not very different from the relative import approach, as long as we do it from the context of mypackage. And again, trying to run this with python mypackage/main.py ends similar:
ModuleNotFoundError: No module named 'mypackage'
How irritating that could be, the interpreter is right, you don't have such package installed.
The solution
For simple Python apps
Just use absolute imports (without the dot), and everything will be fine.
For installable Python apps in development
Use relative imports, or imports with a package name on the beginning, because you need them like this when your app is installed. When it comes to running such module in development, Python can be executed with the -m option:
-m mod : run library module as a script (terminates option list)
So instead of python mypackage/main.py, do it like this: python -m mypackage.main.
In addition to md-sabuj-sarker's answer, there is a really good example in the Python modules documentation.
This is what the docs say about intra-package-references:
Note that relative imports are based on the name of the current module. Since the name of the main module is always "__main__", modules intended for use as the main module of a Python application must always use absolute imports.
If you run python3 moduleA.py3, moduleA is used as the main module, so using the absolute import looks like the right thing to do.
However, beware that this absolute import (from package.module import something) fails if, for some reason, the package contains a module file with the same name as the package (at least, on my Python 3.7). So, for example, it would fail if you have (using the OP's example):
proj/
__init__.py (empty)
proj.py (same name as package)
moduleA.py
moduleB.py
in which case you would get:
ModuleNotFoundError: No module named 'proj.moduleB'; 'proj' is not a package
Alternatively, you could remove the . in from .moduleB import, as suggested here and here, which seems to work, although my PyCharm (2018.2.4) marks this as an "Unresolved reference" and fails to autocomplete.
Maybe you can do this before importing the module：
moduleA.py3
import os
import sys
sys.path.append(os.path.dirname(os.path.abspath(__file__)))
from moduleB import ModuleB
ModuleB.hello()
Add the current directory to the environment directory
Just rename the file from where you run the app to main.py:
from app import app
if __name__ == '__main__':
app.run()
import os
import sys
sys.path.append(os.path.dirname(os.path.abspath(__file__)))
will solve the issue of import path issue.