Quick Fix: Python raises the ImportError: No module named 'stldecompose'
when it cannot find the library stldecompose
. The most frequent source of this error is that you haven’t installed stldecompose
explicitly with pip install stldecompose
. Alternatively, you may have different Python versions on your computer, and stldecompose
is not installed for the particular version you’re using.
In particular, you can try any of the following commands, depending on your concrete environment and installation needs:
π‘ If you have only one version of Python installed:pip install stldecompose
π‘ If you have Python 3 (and, possibly, other versions) installed:pip3 install
π‘ If you don't have PIP or it doesn't work
stldecompose
python -m pip install
π‘ If you have Linux and you need to fix permissions (any one):python3 -m pip install
stldecompose
stldecompose
sudo pip3 install
π‘ If you have Linux with aptpip3 install
stldecompose
--user
stldecompose
sudo apt install
π‘ If you have Windows and you have set up the
stldecompose
py
aliaspy -m pip install
π‘ If you have Anaconda
stldecompose
conda install -c anaconda
π‘ If you have Jupyter Notebook
stldecompose
!pip install
stldecompose
!pip3 install
stldecompose
Problem Formulation
You’ve just learned about the awesome capabilities of the stldecompose
library and you want to try it out, so you start your code with the following statement:
import stldecompose
This is supposed to import the stldecompose library into your (virtual) environment. However, it only throws the following ImportError: No module named stldecompose
:
>>> import stldecompose Traceback (most recent call last): File "<pyshell#6>", line 1, in <module> import stldecompose ModuleNotFoundError: No module named 'stldecompose'
Solution Idea 1: Install Library stldecompose
The most likely reason is that Python doesn’t provide stldecompose
in its standard library. You need to install it first!
Before being able to import the stldecompose
module, you need to install it using Python’s package manager pip
. Make sure pip is installed on your machine.
To fix this error, you can run the following command in your Windows shell:
$ pip install stldecompose
This simple command installs stldecompose
in your virtual environment on Windows, Linux, and MacOS. It assumes that your pip
version is updated. If it isn’t, use the following two commands in your terminal, command line, or shell (there’s no harm in doing it anyways):
$ python -m pip install --upgrade pip $ pip install stldecompose
π‘ Note: Don’t copy and paste the $
symbol. This is just to illustrate that you run it in your shell/terminal/command line.
Solution Idea 2: Fix the Path
The error might persist even after you have installed the stldecompose
library. This likely happens because pip
is installed but doesn’t reside in the path you can use. Although pip
may be installed on your system the script is unable to locate it. Therefore, it is unable to install the library using pip
in the correct path.
To fix the problem with the path in Windows follow the steps given next.
Step 1: Open the folder where you installed Python by opening the command prompt and typing where python
Step 2: Once you have opened the Python
folder, browse and open the Scripts
folder and copy its location. Also verify that the folder contains the pip
file.
Step 3: Now open the Scripts
directory in the command prompt using the cd
command and the location that you copied previously.
Step 4: Now install the library using pip install stldecompose
command. Here’s an analogous example:
After having followed the above steps, execute our script once again. And you should get the desired output.
Other Solution Ideas
- The
ModuleNotFoundError
may appear due to relative imports. You can learn everything about relative imports and how to create your own module in this article. - You may have mixed up Python and pip versions on your machine. In this case, to install
stldecompose
for Python 3, you may want to trypython3 -m pip install stldecompose
or evenpip3 install stldecompose
instead ofpip install stldecompose
- If you face this issue server-side, you may want to try the command
pip install --user stldecompose
- If you’re using Ubuntu, you may want to try this command:
sudo apt install stldecompose
- You can also check out this article to learn more about possible problems that may lead to an error when importing a library.
Understanding the “import” Statement
import stldecompose
In Python, the import
statement serves two main purposes:
- Search the module by its name, load it, and initialize it.
- Define a name in the local namespace within the scope of the
import
statement. This local name is then used to reference the accessed module throughout the code.
What’s the Difference Between ImportError and ModuleNotFoundError?
What’s the difference between ImportError
and ModuleNotFoundError
?
Python defines an error hierarchy, so some error classes inherit from other error classes. In our case, the ModuleNotFoundError
is a subclass of the ImportError
class.
You can see this in this screenshot from the docs:
You can also check this relationship using the issubclass()
built-in function:
>>> issubclass(ModuleNotFoundError, ImportError) True
Specifically, Python raises the ModuleNotFoundError
if the module (e.g., stldecompose
) cannot be found. If it can be found, there may be a problem loading the module or some specific files within the module. In those cases, Python would raise an ImportError
.
If an import statement cannot import a module, it raises an ImportError
. This may occur because of a faulty installation or an invalid path. In Python 3.6 or newer, this will usually raise a ModuleNotFoundError
.
Related Videos
The following video shows you how to resolve the ImportError
:
The following video shows you how to import a function from another folder—doing it the wrong way often results in the ModuleNotFoundError
:
How to Fix “ModuleNotFoundError: No module named ‘stldecompose'” in PyCharm
If you create a new Python project in PyCharm and try to import the stldecompose
library, it’ll raise the following error message:
Traceback (most recent call last): File "C:/Users/.../main.py", line 1, in <module> import stldecompose ModuleNotFoundError: No module named 'stldecompose' Process finished with exit code 1
The reason is that each PyCharm project, per default, creates a virtual environment in which you can install custom Python modules. But the virtual environment is initially empty—even if you’ve already installed stldecompose
on your computer!
Here’s a screenshot exemplifying this for the pandas
library. It’ll look similar for stldecompose
.
The fix is simple: Use the PyCharm installation tooltips to install Pandas in your virtual environment—two clicks and you’re good to go!
First, right-click on the pandas
text in your editor:
Second, click “Show Context Actions
” in your context menu. In the new menu that arises, click “Install Pandas” and wait for PyCharm to finish the installation.
The code will run after your installation completes successfully.
As an alternative, you can also open the Terminal
tool at the bottom and type:
$ pip install stldecompose
If this doesn’t work, you may want to set the Python interpreter to another version using the following tutorial: https://www.jetbrains.com/help/pycharm/2016.1/configuring-python-interpreter-for-a-project.html
You can also manually install a new library such as stldecompose
in PyCharm using the following procedure:
- Open
File > Settings > Project
from the PyCharm menu. - Select your current project.
- Click the
Python Interpreter
tab within your project tab. - Click the small
+
symbol to add a new library to the project. - Now type in the library to be installed, in your example Pandas, and click
Install Package
. - Wait for the installation to terminate and close all popup windows.
Here’s an analogous example:
Here’s a full guide on how to install a library on PyCharm.