在 MAC OS 上安裝了 Python 3.9.1 但仍然說 Python 版本是 2.7

Question

我在我的 MacBook 上安裝了 Python 3.9.1，但是當我使用命令 python --version 時，它顯示它的 python 2.7。 這是我的終端中發生的事情以供參考：

$ python -V
Python 2.7.16
$ brew install pyenv
Updating Homebrew...
==> Auto-updated Homebrew!
Updated Homebrew from 565becc90 to e41981a5c.
Updated 1 tap (homebrew/core).
==> New Formulae
htmltest                   mpdecimal                  vitess
==> Updated Formulae
Updated 158 formulae.

==> Homebrew was updated to version 2.7.7
The changelog can be found at:
  https://github.com/Homebrew/brew/releases/tag/2.7.7
Warning: pyenv 1.2.22 is already installed and up-to-date.
To reinstall 1.2.22, run:
  brew reinstall pyenv
$ pyenv install 3.9.1
python-build: use openssl@1.1 from homebrew
python-build: use readline from homebrew
Downloading Python-3.9.1.tar.xz...
-> https://www.python.org/ftp/python/3.9.1/Python-3.9.1.tar.xz
Installing Python-3.9.1...
python-build: use readline from homebrew
python-build: use zlib from xcode sdk
       
Installed Python-3.9.1 to /Users/myname/.pyenv/versions/3.9.1

$ 
$ python --version
Python 2.7.16

在此先感謝您的幫助！

Answer 1

我在我的 MacBook 上安裝了 Python 3.9.1 但是當我使用命令 python --version 時，它說它的 python 2.7。 這是我的終端中發生的事情以供參考：

$ python -V
Python 2.7.16
$ brew install pyenv
Updating Homebrew...
==> Auto-updated Homebrew!
Updated Homebrew from 565becc90 to e41981a5c.
Updated 1 tap (homebrew/core).
==> New Formulae
htmltest                   mpdecimal                  vitess
==> Updated Formulae
Updated 158 formulae.

==> Homebrew was updated to version 2.7.7
The changelog can be found at:
  https://github.com/Homebrew/brew/releases/tag/2.7.7
Warning: pyenv 1.2.22 is already installed and up-to-date.
To reinstall 1.2.22, run:
  brew reinstall pyenv
$ pyenv install 3.9.1
python-build: use openssl@1.1 from homebrew
python-build: use readline from homebrew
Downloading Python-3.9.1.tar.xz...
-> https://www.python.org/ftp/python/3.9.1/Python-3.9.1.tar.xz
Installing Python-3.9.1...
python-build: use readline from homebrew
python-build: use zlib from xcode sdk
       
Installed Python-3.9.1 to /Users/myname/.pyenv/versions/3.9.1

$ 
$ python --version
Python 2.7.16

在此先感謝您的幫助！

Answer 2

如果您已安裝 python 他們 brew 然后編輯 your.zprofile

添加這一行 export PATH=/usr/local/opt/brew/opt/python@3.9/libexec/bin:$PATH

Answer 3

列出 bin 下的所有 python

ls -l /usr/local/bin/python*

這樣的事情將被列出

lrwxr-xr-x  1 ali  admin  24 Dec 28 22:27 /usr/local/bin/python3 -> /usr/local/bin/python3.9
lrwxr-xr-x  1 ali  admin  39 Mar 31  2022 /usr/local/bin/python3 -> ../Cellar/python@3.9/3.9.12/bin/python3
lrwxr-xr-x  1 ali  admin  46 Mar 31  2022 /usr/local/bin/python3-config -> ../Cellar/python@3.9/3.9.12/bin/python3-config
lrwxr-xr-x  1 ali  admin  41 Mar 31  2022 /usr/local/bin/python3.9 -> ../Cellar/python@3.9/3.9.12/bin/python3.9
lrwxr-xr-x  1 ali  admin  48 Mar 31  2022 /usr/local/bin/python3.9-config -> ../Cellar/python@3.9/3.9.12/bin/python3.9-config

然后將符號鏈接更改為 3.9 或者你的新版本

ln -s -f /usr/local/bin/python3.9 /usr/local/bin/python

退出終端並重新啟動它，它現在應該可以工作了，通常你還必須更改 pip 的符號鏈接，因為它在 python3 目錄下。