Python set up via pyenv

Setting up Python environment

Installation

Check the environment

Might need to create the .zshrc if you don’t have it

touch .zshrc
ls -la

Find homebrew - if don’t have it, need to install it; if have it, might have to update it

which brew
# /opt/homebrew/bin/brew

Install pyenv

brew install pyenv
# check if it exists
which pyenv
# /opt/homebrew/bin/pyenv
echo $PATH 
# check if the path is added

Check version

pyenv --version

Install python through pyenv

Decide which version of python you’d like to install.

pyenv install 3.12.7

After it’s done, check if it exists

which python # does not exist
pyenv global 3.12.7 # set the global python to be this version
pyenv versions 

Modify the .zshrc file: add two lines in the file

nano ~/.zshrc

Type in the following, and save.

eval "$(pyenv init --path)"
eval "$(pyenv init -)"

Check if they are correctly added. If it is, load them by using source

cat ~/.zshrc
source .zshrc

Now check again which python you have,

which python
# /Users/your_name/.pyenv/shims/python
python --version
# Python 3.12.7

# try run python in the terminal
python

# exit python with ctrl + z

Virtual environment

Install the pyenv-virtualenv first.

brew install pyenv-virtualenv

Decide a name for the virtual environment you want. For this one I’m using mypydev312.

pyenv virtualenv 3.12.7 mypydev312
# check what you have 
pyenv virtualenvs
# ~/.pyenv/versions/mypydev312/bin/python

Activate it then try to deactivate it

source .zshrc
pyenv activate mypydev312 # (mypydev312) should be printed in front of your user name

Inside the virtual environment, can also check which python version.

which python
python --version
# run python
python

Deactivate the virtual environment,

pyenv deactivate

Package installation in virtual environment

Inside your virtual environment, try to install some packages.

# if not already activated, do this
pyenv activate mypydev312 
# check pip
which pip
# /Users/your_name/.pyenv/shims/pip
pip install numpy

Use virtual environment with IDE

Rstudio

Can go to Tools -> Global options -> Python, and select the virtual environment.

Pycharm

Go to Settings -> Project -> Python Interpreter. You might see that the packages you want are not available; as we have installed numpy in our virtual environment mypydev312, this is expected.

Set up the virtual environment of our choosing by selecting Add Interpreter -> Add Local Interpreter. Select an existing one in the list.

Now you see the ones we installed (numpy, pandas) are readily available.

VSCode

If you open VSCode and run your python code, but it is missing modules, it suggests that the interpreter isn’t correctly specified. You can see which interpreter you’re using on the bottom right.

Click on it, you can select the one you would like. We are using the virtual environment mypydev312 so this is the one we choose.