How to Change Python Version

Python is a popular programming language that is widely used for a variety of applications, including web development, scientific computing, data analysis, and artificial intelligence. As Python evolves, new versions are released with updated features and performance improvements. In some cases, you may need to change the Python version you are using to ensure compatibility with specific libraries or to take advantage of new language features. This article will guide you through the steps to change your Python version on different operating systems.

Checking Your Current Python Version

Before we learn how to change the Python version, it’s essential to determine which version is currently installed on your system. To do this, open a terminal or command prompt and execute the following command:

python --version

This command will display the version number of the default Python interpreter installed on your system. For example, if you have Python 3.9.2 installed, the command output will be:

Python 3.9.2

Once you have identified your current Python version, let’s proceed with changing it to a different version based on your operating system.

Changing Python Version on Windows

Using Python Launcher

If you have multiple versions of Python installed on your Windows machine, you can use the Python Launcher to switch between them easily. The Python Launcher, also known as py.exe, is a program that can handle multiple Python installations.

To change your Python version using the Python Launcher, use the following command:

py -<version>

Replace <version> with the desired Python version, such as 2, 3, 3.8, etc. For example, to switch to Python 3.8, the command would be:

py -3.8

Changing Environment Variables

Another way to change the Python version on Windows is by modifying the system’s environment variables. Follow these steps to change the Python version using environment variables:

1. Open the Control Panel and navigate to System and Security > System > Advanced system settings.
2. In the System Properties window, click on the Environment Variables button.
3. In the Environment Variables window, locate the Path variable under the System variables section and select it. Click on the Edit button.
4. In the Edit Environment Variable window, you will see a list of paths. Locate the path that points to your current Python version and move it down. Then, locate the path that points to the desired Python version and move it up.
5. Click OK to save the changes and close all windows.

After modifying the environment variables, open a new terminal or command prompt session, and execute the python --version command again to verify that the Python version has changed.

Changing Python Version on macOS

Using Homebrew

If you use Homebrew, a popular package manager for macOS, you can install multiple versions of Python and switch between them effortlessly. Follow these steps to change your Python version using Homebrew:

1. Open a terminal.
2. Install the desired Python version using the following command:

brew install python@<version>

Replace <version> with the Python version you want to install. For example, to install Python 3.8, the command would be:

brew install python@3.8

3. After installation, use the following command to switch to the newly installed Python version:

brew link --overwrite --force python@<version>

Replace <version> with the Python version you just installed.

Using pyenv

Another popular tool for managing Python versions on macOS is pyenv. pyenv allows you to install and switch between multiple Python versions effortlessly. To change the Python version using pyenv, follow these steps:

1. Open a terminal.
2. Install pyenv using Homebrew by executing the following command:

brew install pyenv

3. Add the following lines to your shell configuration file (e.g., .bash_profile, .zshrc) to enable pyenv:

eval "$(pyenv init -)"

4. Apply the changes to the current shell session by running the command:

source <shell configuration file>

Replace <shell configuration file> with the path to your shell configuration file.

5. Install the desired Python version using the following command:

pyenv install <version>

Replace <version> with the Python version you want to install. For example, to install Python 3.8.10, the command would be:

pyenv install 3.8.10

6. Set the newly installed Python version as the global default:

pyenv global <version>

Replace <version> with the Python version you just installed.

Changing Python Version on Linux

Using update-alternatives

On Linux distributions, you can use the update-alternatives command to switch between Python versions available on your system. Follow these steps to change the Python version using update-alternatives:

1. Open a terminal.
2. Execute the following command to list the available Python versions:

sudo update-alternatives --list python

3. Select the desired Python version by executing the following command:

sudo update-alternatives --config python

4. You will be prompted to choose the Python version using the selection number.
5. Enter the selection number and press Enter to switch to the chosen Python version.

Using pyenv

Similar to macOS, pyenv can also be used on Linux systems to manage multiple Python versions. Follow the steps outlined in the Using pyenv section for macOS to install and switch between Python versions using pyenv on Linux.

Conclusion

As Python continues to evolve, changing Python versions may become necessary to leverage new features or ensure compatibility with specific libraries. In this article, we have learned how to change Python versions on different operating systems, including Windows, macOS, and Linux. By following the provided instructions, you can easily switch between Python versions and continue your Python development journey with confidence.

Remember to always verify your Python version after making changes to ensure that the switch was successful:

python --version

Now you are ready to explore the powerful capabilities of Python with different versions at your disposal.