Fixing PATH for Python libraries using Bash

Update: As of python 3.8, the following path should be used:

export PATH=/Library/Frameworks/Python.framework/Versions/3.8/bin:$PATH

If you're using bash, you can store this in your /.bashrc
If you're using zsh, you can store this in your /.zshrc

You have to update the seeking path location, to needed bin folder, in your .zshrc, .bashrc etc.

Example

For /Library/Python/3.8/bin, you can prepend the variable $HOME, and use with the needed path:

export PATH="$HOME/Library/Python/3.8/bin:$PATH"

Epilogue

In current Terminal tab, you have to reload your shell, with the config, by . ~/.zshrc, or .bashrc etc

The error message is telling you to add Python 3 to your path.

To do that, use a text editor to open /Users/<you>/.profile, and as the very last line add:

export PATH=/Users/<you>/Library/Python/3.8/bin:$PATH

Then you'll need to launch a new Terminal window for those settings to take effect. (you could make it take effect in your current shell by entering the line directly into your shell)

[Edit: now that macOS 12.3 has removed all versions of Python, Homebrew is the easiest way to install Python. Fortunately things are simpler because there's only one version of Python on your system and you won't need to override the system's version (because there isn't one any longer).]