What is pyenv
pyenv is a tool used to manage multiple Python versions on a single system. It helps to easily install, switch between, and manage different versions of Python.
Why use it
Avoid version conflicts: Different projects may require different versions of Python.
pyenvallows you to manage and isolate these versions, so you don’t run into compatibility issues.Easier testing: You can test your code across multiple versions of Python without installing each version system-wide.
Better control: You can manage Python versions independently of the system's default Python, preventing changes that could affect system tools or applications that rely on a specific version of Python.
Before you continue with pyenv installation
Make sure Homebrew is installed in the correct location. If you have migrated from Mac using Intel architecture to one with ARM, you might have Homebrew still installed in the old location.
➜ ~ which brew
/opt/homebrew/bin/brew
If your output is /usr/local, you should re-install Homebrew.
How to install pyenv
Install dependencies
➜ ~ brew install openssl readline sqlite3 xz zlib tcl-tk@8Install pyenv using pyenv-installer
- This should install
pyenvand a few useful plugins likepyenv-virtualenv
➜ ~ curl https://pyenv.run | zsh- This should install
Update PATH in
/.zprofile. Add the following:export PYENV_ROOT="$HOME/.pyenv" [[ -d $PYENV_ROOT/bin ]] && export PATH="$PYENV_ROOT/bin:$PATH" eval "$(pyenv init --path)" eval "$(pyenv init -)" eval "$(pyenv virtualenv-init -)"Restart the terminal
How to install Python using pyenv
Run the following to check available CPython versions:
➜ ~ pyenv install --list // Returns quite a few, including CPython 2➜ ~ pyenv install --list | grep -E '^ 3\.[0-9]+' // Returns a list of available CPython 3 versionsInstall a specific CPython version, e.g. 3.11.11:
➜ ~ pyenv install -v 3.11.11
Where is Python installed
Each version is installed in pyenv root directory.
To check all installed versions, run: ls ~/.pyenv/versions/
How to set Python version
Check available versions
Run pyenv versions to see which versions you have available.
The * indicates which version is currently active. By default it is the system's version.
➜ ~ pyenv versions
* system (set by /Users/username/.pyenv/version)
3.9.7
3.11.11
Set system Python version
To switch the version you want to use for the system, use the global command.
➜ ~ pyenv global 3.11.11
system
3.9.7
* 3.11.11 (set by /Users/username/.pyenv/version)
Run python -V to check if the correct version is applied.
➜ ~ python -V
Python 3.11.11
To change it back to default system version
➜ ~ pyenv global system
How to uninstall a particular Python version
You can uninstall a Python version using pyenv uninstall, or simply delete the directory to remove a specific Python version.
Uninstall:
➜ ~ pyenv uninstall 3.11.11
Remove:
➜ ~ rm -rf ~/.pyenv/versions/3.11.11
How to set virtual environment with pyenv
pyenv is primarily a tool for managing Python versions. But it also supports plugins.
One of those supported plugins is pyenv-virtualenv, which helps you manage virtual environments for specific Python versions.
Create virtual environment
When creating a virtual environment, try to use a name that would easily associate it with the project you are working on. Just to make things convenient.
➜ ~ pyenv virtualenv 3.11.11 my_project_venv
Activate virtual environment
➜ ~ pyenv local my_project_venv
This creates a .python-version file in the current working directory, which automatically activates the virtual environment whenever you are in that directory.
➜ ~ pyenv which python
/Users/username/.pyenv/versions/my_project_venv/bin/python
Remove virtual environment
To remove the local version setting, you can do one of the following:
Delete the .python-version file in your directory:
➜ ~ rm .python-version
Or use the --unset command to remove the local version setting:
➜ ~ pyenv local --unset
Once the .python-version file is removed or reset, the system will use the global Python version.