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I'm new to coding and I was wondering if someone could explain what exactly python interpreters/environments do and the how that relates to the python versions and packages that can be used in certain projects.

I was trying to code a twitter bot with python and I use VS code as my IDE. While trying to import tweepy into my python code, I noticed I kept getting an error that it couldn't import. After some googling I realized it was because I had to set the python interpreter of the python file to the one that had tweepy installed to. So I changed it and the error with tweepy was solved. But I noticed that I have a bunch of python interpreters in seemingly different locations (screenshot of the interpreter options I'm given). The interpreter that fixed the issue was the one in the pyenv path.

I had installed pyenv some months back because I wanted my terminal (I'm on macOS) to automatically launch python3 when I typed python into the terminal. However, I don't really know what it does beyond that.

So my questions are:

  1. Why do I have multiple python interpreters? Is there a way to get rid of the ones and just keep the one from pyenv (like clean up the ones in /usr/local/bin/python3, /opt/homebrew/bin/python or /usr/bin/python3 since I'm not using them)? or should I not do that?
  2. What exactly does pyenv do? Is it okay that my python libraries are getting installed to pyenv by default? Or should I change it so that it's getting installed to homebrew or one of the usr/bin paths?

Sorry, this is my first time asking a question here so I might not sound that cohesive.

sel
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  • You should definitely not touch `/usr/bin` at all. You will probably find that the one in `/usr/local/bin` is a wrapper or symlink which eventually resolves to `pyenv` and so you'll want to keep that too. The one in `/opt` is probably unnecessary as long as you use `pyenv` to manage your Python versions, out harmless as such. – tripleee May 03 '22 at 09:07
  • @tripleee Thanks for clarifying why I can/can't delete the python installed in each path. – sel May 03 '22 at 10:16

1 Answers1

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The interpreter is the program which executes a python source file. This is a program like any other, and you can have various versions of it at once (indeed python is quite good at being self contained, and multiple versions will live alongside one another quite happily).

Macs ship with an outdated python 2, used for something in the system. If you remove or update it, things may break. So you install your own python 3 somewhere. If you want to load the new python when you type python in a shell, that shell's $PATH needs to point to the right python. You generally set this in something like ~/.profile.

Pyenv is a tool for managing multiple python interpreters. It's usually used on a per-project basis, to test code against multiple pythons. Further to complicate things, it's often used alongside a virtual environment tool like pipenv. Using it to avoid manually fiddling with $PATH is fine, but a slightly orthogonal use case. All pyenv does is to put little scripts with the same name as python executables somewhere in your $PATH where they supercede anything else. These scripts then figure out which python should get called in this case. So pyenv isn't installing anything, it's just working out which python is going to do it.

The solution to all your problems turns out to be quite simple:

python -m pip install abc

Get into the habit of installing stuff with the python you want to use already set up in the shell, and calling pip like that. That way whatever you use it will always be installed in the right env.

2e0byo
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