我尝试在Mac OS X 10.6.2上切换到Homebrew(在使用fink和macport之后).我安装了python 2.7

brew install python 

问题是,与Macport相反,似乎没有python_select实用程序,我的默认mac python总是默认的

which python

给我吗

/usr/bin/python

而/usr/bin/python不是一个符号链接

我怎样才能使python brew风格成为我的默认python？

我的目标

我正在尝试使用pyenv在我的MBP上并行安装Python 2.7.5和3.6.5.

pyenv 安装

以下如何使用Homebrew在Mac上安装Python 2和3？, 我试过了:

$ pyenv install 3.6.5

哪个错误:

python-build: use openssl from homebrew
python-build: use readline from homebrew
Downloading Python-3.6.5.tar.xz...
-> https://www.python.org/ftp/python/3.6.5/Python-3.6.5.tar.xz
Installing Python-3.6.5...
python-build: use readline from homebrew

BUILD FAILED (OS X 10.13.4 using python-build 20160602)

Inspect or clean up the working tree at /var/folders/d0/t8d3jjp161g2dyrd4k67ypc80000gn/T/python-build.20180426091253.34709
Results logged to /var/folders/d0/t8d3jjp161g2dyrd4k67ypc80000gn/T/python-build.20180426091253.34709.log

Last 10 log lines:
  File "/private/var/folders/d0/t8d3jjp161g2dyrd4k67ypc80000gn/T/python-build.20180426091253.34709/Python-3.6.5/Lib/ensurepip/__main__.py", line 5, in <module>
    sys.exit(ensurepip._main())
  File "/private/var/folders/d0/t8d3jjp161g2dyrd4k67ypc80000gn/T/python-build.20180426091253.34709/Python-3.6.5/Lib/ensurepip/__init__.py", line 204, in _main
    default_pip=args.default_pip,
  File "/private/var/folders/d0/t8d3jjp161g2dyrd4k67ypc80000gn/T/python-build.20180426091253.34709/Python-3.6.5/Lib/ensurepip/__init__.py", line 117, in …

我正在运行Mac OS X 10.11(El Capitan).我想要:

• 保持我的系统版本的Python作为默认值
• 与它一起安装Python 3.5
• 安装OpenCV 3和Python绑定

pyenv按照以下SO答案我安装了Python 3.5:https://stackoverflow.com/a/18671336/1410871

我激活了我的Python 3安装并安装了支持Python 3的OpenCV 3,如下所示:

pyenv shell 3.5.0
brew install opencv3 --with-python3

但是当我启动一个IPython shell并导入时cv2,我收到一个错误:

ImportError                               Traceback (most recent call last)
<ipython-input-1-72fbbcfe2587> in <module>()
----> 1 import cv2

ImportError: No module named 'cv2'

为什么？

我通过 Homebrew 安装了 Python 3.8 和 3.9：

~ brew list | grep python
python@3.8
python@3.9

我想使用 Python 3.9 作为我的默认python3命令。我尝试了以下方法：

~ brew switch python 3.9
Error: python does not have a version "3.9" in the Cellar.
python's installed versions: 3.8.6

我试图卸载 Python 并重新安装它，但它被其他软件包使用：

~ brew uninstall python
Error: Refusing to uninstall /usr/local/Cellar/python@3.8/3.8.6
because it is required by glib and php, which are currently installed.
You can override this and force removal with:
  brew uninstall --ignore-dependencies python

如何使用 Python 3.9？