如何在Mac上将Python3设置为默认的Python版本？

Question

如何在macOS Catalina -- version 10.15.2上将Python 3.8.3设置为默认版本？

我已经完成的步骤：

1. 查找Python 3.8.3的安装位置。

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

我获得的输出如下：

lrwxr-xr-x  1 jeena  admin  36 Mar 20  2019 /usr/local/bin/python -> ../Cellar/python@2/2.7.16/bin/python
lrwxr-xr-x  1 jeena  admin  39 May 20 12:43 /usr/local/bin/python-build -> ../Cellar/pyenv/1.2.18/bin/python-build
lrwxr-xr-x  1 jeena  admin  43 Mar 20  2019 /usr/local/bin/python-config -> ../Cellar/python@2/2.7.16/bin/python-config
lrwxr-xr-x  1 jeena  admin  37 Mar 20  2019 /usr/local/bin/python2 -> ../Cellar/python@2/2.7.16/bin/python2
lrwxr-xr-x  1 jeena  admin  44 Mar 20  2019 /usr/local/bin/python2-config -> ../Cellar/python@2/2.7.16/bin/python2-config
lrwxr-xr-x  1 jeena  admin  39 Mar 20  2019 /usr/local/bin/python2.7 -> ../Cellar/python@2/2.7.16/bin/python2.7
lrwxr-xr-x  1 jeena  admin  46 Mar 20  2019 /usr/local/bin/python2.7-config -> ../Cellar/python@2/2.7.16/bin/python2.7-config
lrwxr-xr-x  1 root   wheel  69 May 20 12:22 /usr/local/bin/python3 -> ../../../Library/Frameworks/Python.framework/Versions/3.8/bin/python3
lrwxr-xr-x  1 root   wheel  76 May 20 12:22 /usr/local/bin/python3-config -> ../../../Library/Frameworks/Python.framework/Versions/3.8/bin/python3-config
lrwxr-xr-x  1 root   wheel  71 May 20 12:22 /usr/local/bin/python3.8 -> ../../../Library/Frameworks/Python.framework/Versions/3.8/bin/python3.8
lrwxr-xr-x  1 root   wheel  78 May 20 12:22 /usr/local/bin/python3.8-config -> ../../../Library/Frameworks/Python.framework/Versions/3.8/bin/python3.8-config
lrwxr-xr-x  1 jeena  admin  37 Mar 20  2019 /usr/local/bin/pythonw -> ../Cellar/python@2/2.7.16/bin/pythonw
lrwxr-xr-x  1 jeena  admin  38 Mar 20  2019 /usr/local/bin/pythonw2 -> ../Cellar/python@2/2.7.16/bin/pythonw2
lrwxr-xr-x  1 jeena  admin  40 Mar 20  2019 /usr/local/bin/pythonw2.7 -> ../Cellar/python@2/2.7.16/bin/pythonw2.7

2. 将默认的Python符号链接更改为我想要使用的版本：

ln -s -f /usr/local/bin/python3.8 /usr/local/bin/python2.7

然后我再次检查了版本：

python --version

我得到的是 --> Python 2.7.16

我还尝试了 alias python="/usr/bin/python3.8"，但很遗憾它仍然是 Python 2.7.16

- Jeena

---

根据 https://dev59.com/3GMl5IYBdhLWcg3wa2XV 的最佳答案，这并不建议，可能会破坏一些东西。 - Kevin Wang

这个回答解决了你的问题吗？如何在OS X上将Python的默认版本设置为3.x？ - Kevin Wang

@KevinWang 我也尝试了使用alias的方法，正如我在问题中提到的那样，它并没有起作用。 - Jeena

所以 > /usr/bin/python3.8 正确地启动了 python3 的 REPL，但是接着使用 > alias python="/usr/bin/python3.8" 命令后再输入 > python 则会启动 python2 的 REPL？ - Kevin Wang

@KevinWang 是的，你说得对。 - Jeena

这确实很奇怪。你使用的是哪个shell？你能否编辑问题并从shell中粘贴出你尝试别名时运行的命令和输出？ - Kevin Wang

Answer 1

我认为您可以运行以下命令：

rm /usr/local/bin/python
ln -s /usr/local/bin/python3.8 /usr/local/bin/python

在您的 ~/.zshrc 或者 ~/.bashrc 文件中，加入以下内容：

export PATH=/usr/local/bin:$PATH

接着打开新终端测试

echo $PATH

确保 /usr/local/bin 在 /usr/bin 之前

- Philippe

---

今天这个答案为我节省了时间。感谢你提供如此简洁的答案！ - Valentino Pereira