Understanding Python Version Confusion on macOS and How to Switch to Python 3.9.2

Many developers, especially those new to macOS, might encounter confusion when trying to identify and switch to a specific version of Python. A common question is why they download Python 3.9.2 but their Mac shows their version as 2.7.16. This article aims to clarify this issue and guide you through managing different Python versions on macOS.

Why Does macOS Show Python 2.7.16 Instead of the Downloaded Python 3.9.2?

On macOS, the default behavior of the `python` command is to reference Python version 2. This has been a standard practice to ensure compatibility with older scripts and applications that may be written in Python 2. When you install a new version of Python, such as Python 3.9.2, it is often placed in a directory that macOS does not automatically modify bydefault.

Why Use Python 3 Explicitly?

There are several reasons to prefer using `python3` over `python` when working with Python scripts. First, it explicitly specifies that you want to use Python 3, avoiding any ambiguity with Python 2. Second, it aligns with modern development practices, which are shifting increasingly toward Python 3. Using `python3` ensures your scripts run with the latest features and improvements available in the Python 3 ecosystem.

For instance, to run Python scripts using Python 3.9.2, you should use the `python3` command. Here is an example:

python3 your_

This command tells the system to use Python 3.9.2, even if your PATH environment variable still includes references to Python 2.7.16.

Managing Multiple Python Versions on macOS

If you need to manage multiple Python versions on your macOS system, follow these steps:

Step 1: Install Python 3.9.2

First, ensure you have installed Python 3.9.2. If you do not have it installed, you can download it from the official Python website () or use brew, a package manager for macOS, with the following command:

brew install 

Brew simplifies the installation and management of different Python versions on macOS.

Step 2: Verify Installations

After installation, you can verify that Python 3.9.2 is installed by running:

python3 --version

This command should return the version of Python 3.9.2 you installed.

Step 3: Update Your PATH Variable (Optional)

To ensure Python 3.9.2 is invoked by default, you can add its location to your system's PATH variable. Run the following command to update your .bash_profile or .zshrc file (depending on your default shell):

echo 'export PATH"/usr/local/opt//bin:$PATH"'  ~_profile

Then, either restart your terminal or run:

source ~_profile

This step is optional but recommended to avoid confusion and streamline your development process.

Conclusion

The confusion around Python versions on macOS is a common challenge for developers. By understanding the default behavior of macOS and using modern tools like brew, developers can efficiently manage and utilize different Python versions. Using the `python3` command ensures you work with Python 3.9.2, even if your system still references older versions by default.

Stay up-to-date with the latest Python versions and leverage the full potential of the Python 3 ecosystem. Happy coding!