# Install Pyenv & Pyenv-virtualenv

## Install Python build dependencies

```bash
xcode-select --install
brew install openssl readline sqlite3 xz zlib
```

## Install using Homebrew

```bash
brew update
brew install pyenv
brew install pyenv-virtualenv
```

## Set up your shell startup scripts

### If using ZSH (default since OS X 10.15)

```bash
echo 'eval "$(pyenv init --path)"' >> ~/.zprofile
echo 'eval "$(pyenv init -)"' >> ~/.zshrc
echo 'eval "$(pyenv virtualenv-init -)"' >> ~/.zshrc
```

### If using Bash

```bash
echo 'export PYENV_ROOT="$HOME/.pyenv"' >> ~/.profile
echo 'export PATH="$PYENV_ROOT/bin:$PATH"' >> ~/.profile
echo 'eval "$(pyenv init --path)"' >> ~/.profile
echo 'if [ -n "$PS1" -a -n "$BASH_VERSION" ]; then source ~/.bashrc; fi' >> ~/.profile
echo 'eval "$(pyenv init -)"' >> ~/.bashrc
echo 'eval "$(pyenv virtualenv-init -)"' >> ~/.bashrc
```

You may need to open a new shell after this.

---

# Use virtualenvs

Each of the below `pyenv <command>` operations is documented [here](https://github.com/pyenv/pyenv/blob/master/COMMANDS.md)

## Install desried python version(s)

```bash
# pyenv install <python_version>
pyenv install 3.7.12
```

## Create a virtualenv

```bash
# pyenv virtualenv <virtualenv_name> <python_version>
pyenv virtualenv myenv 3.7.12
```

## Set a virtualenv as the default for a project/directory

This creates a `.python-version` file that tells `pyenv` which executable the `python` command should point to.

```bash
# To use a virtualenv:
# pyenv local <virtualenv_name>
pyenv local myenv

# To use a python base interpreter:
# pyenv local <python_version>
pyenv local 3.7.12
```

---

# \[Optional\] Install Starship.rs

[starship.rs](https://starship.rs/guide/#%F0%9F%9A%80-installation) displays useful information 
about your terminal environment, such as the version of Python that's currently active.

Your prompt line should then look something like this:

```
tasercake on master [$!] via 🐍 v3.7.12 (myenv) on ☁️ (us-east-1)
❯ 
```