如何在macOS Catalina中将python自制版本设置为默认值

Question

For quite some time now I have been having problems configuring python and as a result I have many versions installed. When I enter the command which -a python python2 python2.7 python3 python3.6 python3.7 python3.8 I get the following:

/usr/bin/python
/usr/bin/python2
/usr/bin/python2.7
/usr/local/bin/python3
/usr/bin/python3
/usr/local/bin/python3.7

But searching by hand I also found:

/usr/local/Cellar/python
/usr/local/Cellar/python@2
/usr/local/Cellar/python@3.8

which python shows that the default python is pointing to systems python, not homebrew

/usr/bin/python

My .bash_profile config is:

export PATH=/usr/local/bin:/usr/local/sbin:/usr/local/opt/:/usr/bin:/bin:/usr/sbin:/sbin:/opt/X11/bin:/usr/local/git/bin

I want to achieve a few things:

1. Control python from Homebrew only.
2. Maintain the factory python installations in MACOS Catalina and remove those that are not needed.
3. Set homebrew's python as my default installation.

Edit 1: After following all the instruction given by @Akbar30bill I have the following error:

Stevens-MacBook-Pro:~ setegonz$ python ––version 

/Users/setegonz/.pyenv/versions/3.8.1/bin/python: can't open file '––version': [Errno 2] No such file or directory

Answer 1

i highly suggest using pyenv its brew compatible and managing python version is easy to install just use

$ brew update
$ brew install pyenv

Add pyenv init to your shell

$ echo -e 'if command -v pyenv 1>/dev/null 2>&1; then\n  eval "$(pyenv init -)"\nfi' >> ~/.bash_profile

Restart your shell

$ exec "$SHELL"

Install Python versions into $(pyenv root)/versions

$ pyenv install 3.8.1
$ pyenv global 3.8.1

it also manages pip version to be linked with current python instalation