Python

Weird Snaky Language

When using python you usually want to set up a virtual environment.

python3 -m venv ~/path/to/project

This is because python will install files in your base installation, and you will quickly pollute your site-packages/ folder in your base install. Therefore you must activate your virtual environment, when your environment is active, python will install packages only local to that environment.

Activating/Deactivating your venv

Once inside your project directory do a lil'

source ./bin/activate

This activates the venv, and is now safe to install packages

deactivate

Deactivates the venv, venv must be activated and deactivated everytime you want to use it.

Custom Prompt Stuff

If you want a custom prompt you can put this inside your .zshrc

plugins=(virtualenv)
function virtualenv_info { 
    [ $VIRTUAL_ENV ] && echo '('`basename $VIRTUAL_ENV`') '
}

And then add this line to themes (I'm using oh_my_zsh)

vim ~/.oh-my-zsh/themes/some_theme
PROMPT+='%{$fg[green]%}$(virtualenv_info)%{$reset_color%}%'

There should be a default prompt that tells you the directory you're in before the shell prompt if you've activated a virtual environment, so test that out before changing it. Taken from this stack overflow page

Creating environment folders

This article has great advice
The way I set up my python virtual environments is as follows (method #1 from the above article). Keeping the venvs inside the project directories themselves.

~/
│
└── Coding/
   │
   └── python/
       │
       ├── first-project/
       │   │
       │   ├── src/
       │   │
       │   └── venv_first/
       │
       └── second-project/
           │
           ├── src/
           │
           └── venv_second/

pip install

If you have activated a virtual environment, pip will install packages into your venv folder, if you have not then pip will install programs into a default location on your computer.

MacOS: /usr/local/lib/python2.7/site-packages
Fedora37: $HOME/.local/lib/python3.11/site-packages

Note: MacOS will install to a different location if you specify pip3. The way to find where a specific package resides is by using the pip show <package name> command.

What the heck is if __name__ == "__main__"

This is a way of running python as a script. When you run a script in the terminal you run it in the top-level code environment. So any code after this conditional only runs when you are in a top-level code environment. I.e a shell, where the automatically defined variable __name__ == '__main__'

When imported as a module for example, __name__ == '__<module_name>__' and the code after this conditional will not run.