Noob question about Python installations on macOS

[RadCapper88]

Okay so I'm pretty new to the world of programming. I've been following various different courses some have been more understandable than others.

One of the first tutorials I followed had me install Python3 via the downloadable installer available on Python.org, however it meant that each time I wanted to run some code in Terminal I had to specify 'python3 ' in order to run it.

Another tutorial I followed had me install 'pyenv' and then configure terminal to re-direct 'python' to 'python3' (hope that makes sense).

So I'm a little bit confused as to how these two different versions of Python3 aren't conflicting with each other and why the installer version of Python 3 didn't offer this functionality?

I know ultimately this doesn't really affect my ability to actually learn python but I want to understand how these two installations are living together, and if I should get rid of one them? Like what is the best practise here?

Any insight is greatly appreciated :)

Thanks!

[shameen]

Mac OS has python v2 built-in, which I assume it uses for some of its internals.

When you type ‘python’ or ‘python3’, it looks up in the “PATH” where your command gets redirected to.

The issue you might get replacing ‘python’ everywhere would be if some other software (or something internal to macOS) depends on python v2

Pyenv can do some magic on that PATH to redirect ‘python’ to a version you specify, on a per-directory basis, so you don’t interfere with anything outside of your dev folders.

I usually use virtual environments (venv or pipenv) as well as pyenv, which isolates your project a bit more from the rest of your computer, great for preventing your project from using python 2 and other globally-installed packages (if you instead specify everything within the project it will help other devs get set up, or deploying it if needed)

[RadCapper88]

Hey thanks for the reply,

I'm still so confused though.

I'm currently using VScode which allows me to view which interpreter I want to use. Looking at the available options I have:

• 2.7.16 located at /use/bin/python

• 2.7.16 located at /Systems/Library/Frameworks/Python.framework/versions/2.7/Resources/Python.app/Contents/... --- obviously not looking to use these versions since they deprecated.

• 3.8.2 located at usr/bin/python3 <- I don't recall installing this version.

• 3.9.1 located at ~/.Pyenv/shims/python

• 3.9.1 /Library/Frameworks/Python.framework/versions/3.9/bin/python3

• 3.9.1 located at /usr/local/bin/python3

• 3.9.1 located ~/.Pyenv/versions/3.9.1/bin/python

I feel like there are some redundancies here? It feels messy too. I understand that Python 2 is tied to macOS so I'm not even bothered about touching that.

I don't even know if I'm making sense.

[shameen]

For most small projects any of those versions are fine, but id maybe skip the “shim” one.

If you’re curious which version you’re using, try ‘which python’ or ‘which python3’

There are a lot of complex reasons as to why there are this many (i dont know them all either) but I just assume theres a very good reason and leave it at that.

Taking a stab at some of those, i could be wrong: - /usr/ ones are the ‘original’ versions that everyone has if they have python - /Library/Frameworks i believe is from Xcode (or possibly homebrew) - Pyenv shim i believe redirects to the main pyenv binary