How to Install Cython in Python

Cython is a powerful tool for optimizing Python code. It compiles Python to C for better performance. This guide will help you install Cython easily.

Prerequisites for Installing Cython

Before installing Cython, ensure you have Python installed. Check your Python version using python --version.

You also need a C compiler. On Linux, install build-essential. On macOS, install Xcode. On Windows, install Visual Studio Build Tools.

For more details, see our guide on Install Python on Ubuntu in 5 Steps.

Install Cython Using pip

The easiest way to install Cython is with pip. Run this command in your terminal:

pip install cython

This installs Cython globally. For local installation, use a virtual environment.

Verify Cython Installation

Check if Cython installed correctly. Run this Python code:

import cython
print("Cython version:", cython.__version__)

You should see the installed version number as output.

Install Cython in a Virtual Environment

For project-specific installation, use a virtual environment. First create one:

python -m venv myenv
source myenv/bin/activate  # On Linux/macOS
myenv\Scripts\activate     # On Windows

Then install Cython inside the activated environment.

Install Cython with Conda

If you use Anaconda, install Cython with:

conda install -c anaconda cython

This ensures compatibility with other Conda packages.

Compile Python Code with Cython

Here's a simple example. Create a file example.pyx:

def say_hello(name):
    return f"Hello, {name}!"

Create a setup.py file:

from distutils.core import setup
from Cython.Build import cythonize

setup(ext_modules=cythonize("example.pyx"))

Compile with:

python setup.py build_ext --inplace

Troubleshooting Common Issues

If you get compiler errors, ensure you have all build tools installed. On Windows, install the correct Visual Studio version.

For permission errors, consider installing packages locally instead of globally.

Conclusion

Installing Cython is straightforward with pip or conda. It boosts Python performance significantly. Remember to install build tools first.

For more Python installation guides, check our article on installing multiple Python versions.