Virtual environments

1. Version: pyenv versions to show which python version you have. pyenv global 3.8.8 to switch to 3.8.8. Switch to the specific folder, and use pyenv local 3.6.6 to use 3.6.6 specifically for that project folder.
2. For specific python projects, switch to that folder and use pipenv install. Use pipenv install numpy to install numpy for that project. Use pipenv shell to activate the environment. Inside the shell, use pip install --user <packagename> to install packages. To remove the environment use pipenv --rm.
3. Troubleshoot: If you type a package name wrongly in pipenv install, remove the wrong name in pip file directly. If pip cannot be found, use python get-pip.py — force-reinstall in pipenv shell.