I've just installed Python version 3.11 (I also moved versions 3.8 and 3.9 to the trash from my Applications folder).

I can see it in the following:

$ myname@name-MBP miniconda3 % ls /usr/local/bin/py*
/usr/local/bin/pydoc3           /usr/local/bin/python3-intel64
/usr/local/bin/pydoc3.11        /usr/local/bin/python3.11
/usr/local/bin/python3          /usr/local/bin/python3.11-config
/usr/local/bin/python3-config       /usr/local/bin/python3.11-intel64

(Any additional recommendations on whether I need to clean things up would be much appreciated.)

Checking python3 --version still displays Python 3.8.13.

First attempt to solve

Initially I tried installing it from the command line using homebrew and specifying the version:

brew install [email protected]

I also tried using conda, but neither of these worked.

Second attempt to solve

My initial thought was to check my PATH (I think this is how Python decides which version to use, but please correct me if I'm wrong).

This still only contained version 8 paths:

/Users/myname/miniconda3/lib/python38.zip
/Users/myname/miniconda3/lib/python3.8
/Users/myname/miniconda3/lib/python3.8/lib-dynload
/Users/myname/.local/lib/python3.8/site-packages
/Users/myname/miniconda3/lib/python3.8/site-packages

So I added the Python3.11 path to it using

PYTHONPATH="/usr/local/bin/pydoc3.11/:$PYTHONPATH"
export PYTHONPATH

Now it includes the v3.11 path when I print out sys.path:

/usr/local/bin/python3.11
/usr/local/bin/pydoc3.11
/Users/myname/miniconda3
/Users/myname/miniconda3/lib/python38.zip
/Users/myname/miniconda3/lib/python3.8
/Users/myname/miniconda3/lib/python3.8/lib-dynload
/Users/myname/.local/lib/python3.8/site-packages
/Users/myname/miniconda3/lib/python3.8/site-packages

But the python3 --version output is still unchanged.

Questions

I'm nervous to keep playing around with the contents of my path and entering random command line executions to try to solve this because I really have no clue what I'm doing.

What's happening here?

How can I get the output of python3 --version to be 3.11?

CodePudding user response：

So first thing to understand is setting the variable PYTHONPATH will not affect which version of python is executed by the shell. The shell (bash/zsh) only knows to scan the paths in the PATH env var to figure out all the executables.

Now there are two ways to solve this.

1. Using the [email protected] from homebrew.

There are several downsides to using this method. Currently, the default python3 by brew is 3.10.x. Whenever you will install any cask or formula that depends on python@3, it'll invariably install the python@3 formula aka 3.10.x. Installing python3 will make brew symlink 3.10.x into /opt/homebrew/bin.

Python 3.11.x can be used by installing [email protected] and invoking python3.11. This should drop you into the Python 3.11 interpreter. Append all python executable names with the version like pip will be pip3.11

Trying to force 3.11 over 3.10 links will be complicated and cause instability. It'll only cause frustration during development.

2. Using VirtualEnvs

Your best bet for the most stable and no-headache approach to python is to create virtual envs using either venv or pyenv. use pyenv-virtualenv for max ease of use.

One limitation of venv is that it'll create a virtualenv of the same version that invoked it. Aka if you do brew install python@3 && python3 -m venv <folder>, it'll create virtualenv of python3. For 3.11 you'll have to brew install [email protected] && python3.11 -m venv <folder>. Pyenv on the other hand can install any version of python.

Go through https://www.dataquest.io/blog/a-complete-guide-to-python-virtual-environments/ and https://github.com/pyenv/pyenv-virtualenv to understand and learn more.