Windows

インストーラーで各バージョンをインストール
パワーシェルでpy --listで可能なバージョンが表示
使用する場合は例えばpy -3.10 -m venv .venv

Mac

pyenv

インストール
```
brew install pyenv
```

PATHを通す

echo 'export PYENV_ROOT="$HOME/.pyenv"' >> ~/.zshrc
echo '[[ -d $PYENV_ROOT/bin ]] && export PATH="$PYENV_ROOT/bin:$PATH"' >> ~/.zshrc
echo 'eval "$(pyenv init - zsh)"' >> ~/.zshrc

シェルを再起動
```
exec "$SHELL"
```
- 推奨ビルド環境
- pyenvがダウンロードしたPythonのビルドが環境の依存性で失敗する、またはランタイムで挙動がおかしいことがあるらしい。
- そこで、次のインストールが推奨されているので、実行する。
```
brew install openssl readline sqlite3 xz zlib tcl-tk@8 libb2
```
  すると以下のメッセージが出るが、とりあえず実行しないでおく
  
  sqlite is keg-only, which means it was not symlinked into /opt/homebrew,
  because macOS already provides this software and installing another version in
  parallel can cause all kinds of trouble.
  
  If you need to have sqlite first in your PATH, run:
  echo 'export PATH="/opt/homebrew/opt/sqlite/bin:$PATH"' >> ~/.zshrc
  
  For compilers to find sqlite you may need to set:
  export LDFLAGS="-L/opt/homebrew/opt/sqlite/lib"
  export CPPFLAGS="-I/opt/homebrew/opt/sqlite/include"
  
  For pkg-config to find sqlite you may need to set:
  export PKG_CONFIG_PATH="/opt/homebrew/opt/sqlite/lib/pkgconfig"
  ...
  zlib is keg-only, which means it was not symlinked into /opt/homebrew,
  because macOS already provides this software and installing another version in
  parallel can cause all kinds of trouble.
  
  For compilers to find zlib you may need to set:
  export LDFLAGS="-L/opt/homebrew/opt/zlib/lib"
  export CPPFLAGS="-I/opt/homebrew/opt/zlib/include"
  
  For pkg-config to find zlib you may need to set:
  export PKG_CONFIG_PATH="/opt/homebrew/opt/zlib/lib/pkgconfig"
  
  ...
  The sqlite3_analyzer binary is in the sqlite-analyzer formula.
  
  tcl-tk@8 is keg-only, which means it was not symlinked into /opt/homebrew,
  because this is an alternate version of another formula.
  
  If you need to have tcl-tk@8 first in your PATH, run:
  echo 'export PATH="/opt/homebrew/opt/tcl-tk@8/bin:$PATH"' >> ~/.zshrc
  
  For compilers to find tcl-tk@8 you may need to set:
  export LDFLAGS="-L/opt/homebrew/opt/tcl-tk@8/lib"
  export CPPFLAGS="-I/opt/homebrew/opt/tcl-tk@8/include"
  
  For pkg-config to find tcl-tk@8 you may need to set:
  export PKG_CONFIG_PATH="/opt/homebrew/opt/tcl-tk@8/lib/pkgconfig"
- 特定のバージョンをインストール
```
pyenv install 3.11
```
- Pythonバージョンの変更
  
  pyenv shell -- select just for current shell session
  pyenv local -- automatically select whenever you are in the current directory (or its subdirectories)
  pyenv global -- select globally for your user account