Where I keep my Python notes for starting projects

• brew install will install at the system level. So pyenv (the python picker) was done this way
• pip install will install into the currently active pyenv python version. So pick this for global things per python version, like pip install pipenv.
• pipenv install will install dependencies into the current project.

I use pyenv to manage the operating Python version.

Carefully follow the prerequisites and numbered steps in the Mac install, which starts by using Homebrew.

Then add any requisite lines to the .bashrc file or .zprofile file (it will tell you what to add).

Note that you'll need to restart the shell to make it all work.

Do the Ubuntu install using auto-installer.

On Ubuntu 18.04, before doing the below to install Python 3.7, need to do the following:

sudo apt-get update
sudo apt-get install build-essential libffi-dev libssl-dev libbz2-dev libreadline-dev libsqlite3-dev

pyenv install 3.7.8
pyenv global 3.7.8
pyenv versions

I use pipenv to manage the dependencies for each project. I prefer to keep those dependencies in the project folder, which these steps allow.

I've installed using pip3 install pipenv

Also importantly added export PIPENV_VENV_IN_PROJECT=1 to my .bash_profile

• Start a git repo
• Add .gitignore
• cd into the project

• pipenv install jupyterlab
• pipenv run jupyter lab

or, if not using Jupyter, jut:

• pipenv install

NOTE: if you run into lock problems with pipenv, try adding --skip-lock

NOTE: Jupyter notebook and lab both take in the variables from a .env file if it exists, so the below is not needed.

pipenv install python-dotenv

Then...

from dotenv import load_dotenv
import os
load_dotenv()

DATABASE_PASSWORD = os.getenv("DATABASE_PASSWORD")

Just don't use spaces in the .env file. So:

DATABASE_PASSWORD=`sekrit`

Could not import the lzma module. Your installed Python is incomplete. Attempting to use lzma compression will result in a RuntimeError.

I got this from early on with my fresh python install. Looked up the fix and found this:

• pip freeze > latestPackages.txt
• pyenv uninstall 3.7.3
• brew install xz (This is how you pick up the correct lzma macOS)
• pyenv install 3.7.3

The brew command said that xz was already installed and up to date. So maybe it wasn't when I first installed python?

With Python 3.8 I couldn't Jupyter Lab to recognize the modules I install in the environment. It's not referencing the kernel.json file in the environment, but looks to a more global version instead.

Jupyter Notebook works, and Jupyter lab works in Python 3.7.7.