How to install Matplotlib on Mac 10.7 in virtualenv?

Installing Matplotlib on Mac 10.7 within a virtual environment ensures isolated package management and prevents conflicts with system-wide Python installations. Here's a step-by-step guide to set up Matplotlib in virtualenv.

Creating and Activating Virtual Environment

First, create a new virtual environment and activate it ?

virtualenv myenv
source myenv/bin/activate

Your terminal prompt should change to indicate the virtual environment is active, showing (myenv) at the beginning.

Installing Matplotlib

With the virtual environment activated, install Matplotlib using pip ?

pip install matplotlib

This command downloads and installs Matplotlib along with its dependencies like NumPy and other required packages.

Verifying Installation

Test the installation by creating a simple plot ?

import matplotlib.pyplot as plt
import numpy as np

x = np.linspace(0, 10, 100)
y = np.sin(x)

plt.plot(x, y)
plt.title('Simple Sine Wave')
plt.xlabel('X values')
plt.ylabel('Y values')
plt.show()

Saving Package Requirements

Generate a requirements file to track installed packages ?

pip freeze > requirements.txt
cat requirements.txt

This creates a requirements.txt file listing all installed packages with their versions, making it easy to recreate the environment later.

Troubleshooting Mac 10.7 Issues

If you encounter compilation errors on Mac 10.7, install the required development tools ?

xcode-select --install
brew install pkg-config freetype

You may also need to upgrade pip before installing Matplotlib ?

pip install --upgrade pip
pip install matplotlib

Conclusion

Using virtualenv ensures clean Matplotlib installation on Mac 10.7 without affecting system Python. Always activate your virtual environment before working on projects requiring Matplotlib.