Python on ARM M1 macOS

Sooner than later as a mac user will end up using python, and you ask your self this question

Which Python am I using?

Or most specifically which python interpreter is used when a run a Python based program (like ansible). You will likely have available python3 in a ARM based macOs. But python2 is not available any more in case that you need it this guide will come in handy.

QFINM377:~ antonio.sanchez$ type python3
python3 is /usr/bin/python3

Installing and switching different Python versions

Python is an interpreted language an opposite to GoLang, or Java, so in case that your python application needs some dependencies (requirements.txt) is advisable to not to mess with built-in python interpreter when you use pip install. https://github.com/pyenv/pyenv does a incredible job installing and switching python versions without a pain.

Install pyenv like described

brew update
brew install pyenv

Double check that pyenv is installed in $HOME/.pyenv

Add in your .bash_profile and reload with source .bash_profile.

export PYENV_ROOT="$HOME/.pyenv"
command -v pyenv >/dev/null || export PATH="$PYENV_ROOT/bin:$PATH"
eval "$(pyenv init -)"

Now you can install python2 and python3 and switch between them

$ pyenv install --list
$ pyenv install 3.10.11
$ pyenv install 2.7.18
$ pyenv global 3.10.6

if you see this warning install xz library.

ModuleNotFoundError: No module named '_lzma'
WARNING: The Python lzma extension was not compiled. Missing the lzma lib?

$ brew install xz

Virtual environments using pyenv

You can create and use virtual environment out of your installed python version.

$ pyenv versions
  system
  2.7.18
  * 3.10.11 (set by /Users/antonio.sanchez/.pyenv/version)
$ pyenv virtualenv 2.7.18 my-python-app-env

Your shell prompt will change once the virtual environment is activated. You can install dependencies without conflicting with other installations.

$ pyenv activate my-python-app-env

# installed requirements
$ (my-python-app-env) pip install -r my-python-app-dependencies.pip