Python2のサポートが終了したので、３系をメインに切り替えしようと思った。
２系が必要になったら後で切り替えられるようにしたい
設定方法
brew install python3でpython3をインストール
~ brew install python3 2065ms Fri Jan 31 07:51:57 2020
Updating Homebrew...
==> Downloading https://homebrew.bintray.com/bottles/python-3.7.6_1.mojave.bottle.tar.gz
Already downloaded: /Users/pcuser/Library/Caches/Homebrew/downloads/814567972a37dafb5f922cc993d13dd59c468da5113385e93d1bbfceccaba83f--python-3.7.6_1.mojave.bottle.tar.gz
==> Pouring python-3.7.6_1.mojave.bottle.tar.gz
Error: The `brew link` step did not complete successfully
The formula built, but is not symlinked into /usr/local
Could not symlink Frameworks/Python.framework/Headers
Target /usr/local/Frameworks/Python.framework/Headers
is a symlink belonging to python@2. You can unlink it:
brew unlink python@2
To force the link and overwrite all conflicting files:
brew link --overwrite python
To list all files that would be deleted:
brew link --overwrite --dry-run python
Possible conflicting files are:
/usr/local/Frameworks/Python.framework/Headers -> /usr/local/Cellar/python@2/2.7.15_1/Frameworks/Python.framework/Headers
/usr/local/Frameworks/Python.framework/Python -> /usr/local/Cellar/python@2/2.7.15_1/Frameworks/Python.framework/Python
/usr/local/Frameworks/Python.framework/Resources -> /usr/local/Cellar/python@2/2.7.15_1/Frameworks/Python.framework/Resources
/usr/local/Frameworks/Python.framework/Versions/Current -> /usr/local/Cellar/python@2/2.7.15_1/Frameworks/Python.framework/Versions/Current
==> /usr/local/Cellar/python/3.7.6_1/bin/python3 -s setup.py --no-user-cfg install --force --verbose --install-scripts=/usr/local/Cellar/pytho
==> /usr/local/Cellar/python/3.7.6_1/bin/python3 -s setup.py --no-user-cfg install --force --verbose --install-scripts=/usr/local/Cellar/pytho
==> /usr/local/Cellar/python/3.7.6_1/bin/python3 -s setup.py --no-user-cfg install --force --verbose --install-scripts=/usr/local/Cellar/pytho
==> Caveats
Python has been installed as
/usr/local/bin/python3
Unversioned symlinks `python`, `python-config`, `pip` etc. pointing to
`python3`, `python3-config`, `pip3` etc., respectively, have been installed into
/usr/local/opt/python/libexec/bin
If you need Homebrew's Python 2.7 run
brew install python@2
You can install Python packages with
pip3 install <package>
They will install into the site-package directory
/usr/local/lib/python3.7/site-packages
See: https://docs.brew.sh/Homebrew-and-Python
==> Summary
🍺 /usr/local/Cellar/python/3.7.6_1: 3,977 files, 60.8MB
インストールしたらPython2のライブラリのパスとコンフリクトしていると言われる
もしPython2を普段使わない人はここでUnlinkしてしまうのがいいかかも
ログにある通りUnlinkサブコマンドがあるので--dry-runオプションをつけて実行
brew link --overwrite --dry-run python
! ~ brew link --overwrite --dry-run python 26.7s Fri Jan 31 07:57:52 2020
Would remove:
/usr/local/Frameworks/Python.framework/Headers -> /usr/local/Cellar/python@2/2.7.15_1/Frameworks/Python.framework/Headers
/usr/local/Frameworks/Python.framework/Python -> /usr/local/Cellar/python@2/2.7.15_1/Frameworks/Python.framework/Python
/usr/local/Frameworks/Python.framework/Resources -> /usr/local/Cellar/python@2/2.7.15_1/Frameworks/Python.framework/Resources
/usr/local/Frameworks/Python.framework/Versions/Current -> /usr/local/Cellar/python@2/2.7.15_1/Frameworks/Python.framework/Versions/Current
こんなの出てきたけど別に問題ないので--dry-runオプションを外して実行
brew link --overwrite python
~ brew link --overwrite python 1526ms Fri Jan 31 07:57:54 2020
Linking /usr/local/Cellar/python/3.7.6_1... 24 symlinks created
リンクを更新した。
ただこのままだとバージョンが2系のままになってしまっているので
alias python=python3でエイリアスを設定する。
おまけ
pipもデフォルトはPython2なのでエイリアスを設定しておくと変なエラーを吐かなくていいかも
visudo 編集画面
反映できているか確認した図