ModuleNotFoundError: No module named 'matplotlib'

Posted in Python by Dirk - last update: Feb 05, 2024

Python raises the ModuleNotFoundError: No module named 'matplotlib when it is unable to find the matplotlib library. The most likely cause is that you didn’t install matplotlib in the environment where you are running your code. Quick fix: install matplotlib using: the pip install matplotlib command

Possible causes and solutions

Matplotlib is a widely-used open-source plotting library for the Python programming language. It provides a flexible and comprehensive set of tools for creating static, interactive, and animated visualizations in Python. Matplotlib is often used for generating a wide range of plots and charts, including line plots, scatter plots, bar plots, histograms, 3D plots, and more.

Sample code:

import matplotlib.pyplot as plt

# Sample data
x = [1, 2, 3, 4, 5]
y = [2, 4, 6, 8, 10]

# Creating a line plot
plt.plot(x, y)

# Adding labels and title
plt.xlabel('X-axis')
plt.ylabel('Y-axis')
plt.title('Simple Line Plot')

# Displaying the plot
plt.show()

And when trying to run the code you get the ’no module named error’ - you try running your code, and there it is:

Traceback (most recent call last):
  File "myfile.py", line 1, in <module>
ModuleNotFoundError: No module named 'matplotlib'

Luckily, it is easy to fix. Below you can find the most common causes and how to fix them:

‘matplotlib’ Library is not installed

In your code you are importing the ‘matplotlib’ module

import matplotlib.pyplot as plt

which generates the ModuleNotFoundError: No module named 'matplotlib’. The the most common cause for this error: the environment where you are running your code doesn’t have the matplotlib library installed.

You can use the following command in the terminal or command prompt to check if the matplotlib library is installed:

pip show matplotlib

If matplotlib is not installed you will get this result:

WARNING: Package(s) not found: matplotlib

Solution:

pip install matplotlib

‘matplotlib’ Module installed in the Wrong Directory

It is possible that you did install the matplotlib module, but that the directory where you installed it is not in the Python path.

You can check the Python path in a few different ways:

1. Using sys module in Python:

Open a Python script or the Python interpreter and run the following code:

import sys
print(sys.path)

This will print a list of directories that make up the Python path.

2. Using Command Line

Open a command prompt or terminal and run:

Windows

echo %PYTHONPATH%

Unix/Linux/macOS

echo $PYTHONPATH

If the PYTHONPATH environment variable is set, it will display the directories in the Python path.

Solution: Move the matplotlib module to a directory that is included in the Python path or add the matplotlib module’s directory to the sys.path using sys.path.append().

‘matplotlib’ not installed in Virtual Environment

Even if you have matplotlib installed in on your computer, if you are using a virtual environment you cannot access it from this environment.

If you are using virtual environments, ensure that the virtual environment is activated, and that the matplotlib modules is installed within this environment.

Installation is simple:

pip install matplotlib

File Naming Conflicts:

It is not really likely - but if you happen to have a ```matplotlib.py`` file in your environment and you also installed the standard matplotlib library it will cause a conflict. Rename your script/module to avoid conflicts with existing module names.