How to Check Which Python Version is Installed on Your Mac

As a Mac user, it’s important to know which version of Python is installed on your system, especially if you’re venturing into programming or data science. Python is one of the most popular programming languages today, widely used for everything from web development to artificial intelligence. Whether you are a beginner learning the ropes or an experienced developer looking to ensure you’re working with the right version, knowing how to check your Python installation is crucial. In this article, we’ll walk you through the steps and methods to check which Python version is running on your Mac.

Understanding Python Versions

Before diving into the actual methods, let’s take a moment to understand why knowing your Python version matters. Python has two main versions currently in use: Python 2 and Python 3. Python 2 is no longer officially supported since January 1, 2020, which means it does not receive updates or security fixes. Therefore, using Python 3 is highly recommended, as it includes many improvements and new features.

Different projects and libraries may depend on specific Python versions, which can lead to compatibility issues if you’re not using the version they require. By determining which version you have installed, you can avoid potential roadblocks and ensure a smoother development process.

Checking Python Version via Terminal

The Terminal app on your Mac is a powerful tool that allows you to interact with your system at a deeper level. Checking your Python version is straightforward with a few commands. To start, you’ll need to launch the Terminal. You can find it in the Utilities folder within your Applications folder or by searching for “Terminal” using Spotlight.

Once you have Terminal open, you can check your Python version by entering one of the following commands:

python --version

This command is intended for Python 2.x installations. If you happen to have Python 2 installed, you’ll see output similar to this:

Python 2.7.16

However, if you want to check for Python 3 specifically, you’ll need to use:

python3 --version

This command provides the version of Python 3 that’s currently installed. For example, you might see:

Python 3.8.5

This distinction is particularly important; since many systems, including macOS, come with both versions pre-installed, ensuring you’re aware of which one you’re using is key.

Checking Python Version in a Script

If you are working on a Python script or you prefer to check the version programmatically, you can do so with a simple script. Open a text editor or your preferred IDE, and enter the following lines:

import sys
print(sys.version)

Save this file as check_version.py, then run it through the Terminal by executing:

python check_version.py

or, if you are checking Python 3:

python3 check_version.py

The output will give you detailed information about your Python version, which may look like this:

3.8.5 (default, Jul 20 2020, 08:29:09) 
[GCC 4.2.1 Compatible Apple LLVM 11.0.3 (clang-1103.0.32.62)]

This line shows the version number along with additional details about your build environment, offering more context about your Python installation.

Using the Python Interpreter

Another approach to check your installed version is by using the Python interpreter itself. This method will allow you to get hands-on with Python while determining the version you have. Again, open your Terminal and simply type:

python

or for Python 3 use:

python3

Once you hit enter, you will enter the Python shell, which should display some version information right at the top. It will appear something like this:

Python 3.8.5 (default, Jul 20 2020, 08:29:09)
[GCC 4.2.1 Compatible Apple LLVM 11.0.3 (clang-1103.0.32.62)] on darwin

To exit the interpreter, simply type exit() or press Ctrl + D. The interpreter not only shows the version but also provides an opportunity to start writing Python code directly.

Managing Multiple Python Versions

As a developer, you might find yourself needing to manage multiple Python installations. This is common when you’re working on different projects that require different versions. One effective way to manage versions is through a version management tool like pyenv. This tool allows you to easily switch between multiple versions of Python without much hassle.

You can install pyenv using Homebrew. Here are the steps:

brew update
brew install pyenv

Once installed, you can list available versions with:

pyenv install --list

After selecting a version, you can install it using:

pyenv install 3.9.1

After installation, you can set the global Python version with:

pyenv global 3.9.1

This makes it easier to manage your projects without running into version conflicts.

Updating Your Python Version

If you find that you’re using an outdated Python version, updating it is essential. The best approach for updating depends on how Python was installed initially. If you used Homebrew, you can update Python through the following commands:

brew update
brew upgrade python

This will ensure that you have the latest version of Python installed. You can then confirm the update by rechecking the version using any of the previous methods.

If you originally installed Python via the official installer from Python.org, you would need to download the latest version from the site and run the installer. This process will guide you to the latest version while preserving your existing Python settings and packages.

Using Virtual Environments

Creating a virtual environment is another good practice that can help you manage different projects with specific package requirements. Virtual environments allow you to set up isolated spaces for different projects and their dependencies without affecting the global Python installation.

To create a virtual environment using the built-in venv module in Python 3, first navigate to your project directory in Terminal and execute:

python3 -m venv myenv

This command will create a folder named myenv that contains a standalone Python installation. To activate this virtual environment, you would use:

source myenv/bin/activate

You can then check the Python version within this environment, which allows you to install and use project-specific libraries without command interference.

Conclusion

In this guide, we explored various methods to determine which Python version is installed on your Mac. Understanding your Python version is crucial for ensuring compatibility with your projects and libraries. Whether you check it using the Terminal, a script, the Python interpreter, or employ tools like pyenv, you now have all the information you need. Managing Python versions effectively can save you a lot of time and trouble in your development journey.

With this knowledge, you are well-equipped to navigate the Python landscape on your Mac. As you continue to develop your skills in Python programming, remember that keeping your environment up to date is a key factor in becoming a successful Python developer. Happy coding!