[promer]

The assertion that seemed incorrect was that I was recommending an option that would install libraries to the system Python.

Xcode does put a binary with the name python3 into `/usr/bin`. This is not a system Python, but set that aside.

Can you explain how someone might pip install libraries to this instance of Python?

[swiftcoder]

Once Xcode's python is installed, `pip3 install ...` will install libraries to that python installation (assuming you haven't aliased pip3 to another installation, as it appears the anaconda installer did)

[promer]

The install by xcode of a python3 binary in `/usr/bin` does not come with its own copy of pip3.

So either your command will fail to install or it will use a version of pip that is on PATH but was installed by some other version of python. So in either case you can't install a library into what you are mistakenly calling a system python.

So the original assertion was not true and you have not been able to make up an ex post justification for it.

[swiftcoder]

I have a `/usr/bin/pip3`, and it appears to have been installed at the same time as the rest of XCode. Not sure what's up with your install:

  % ls -la /usr/bin/(pip3|python3|clang)
  -rwxr-xr-x  77 root  wheel  119008  4 Aug 12:31 /usr/bin/clang
  -rwxr-xr-x  77 root  wheel  119008  4 Aug 12:31 /usr/bin/pip3
  -rwxr-xr-x  77 root  wheel  119008  4 Aug 12:31 /usr/bin/python3

[promer]

Yes, you are correct. pip3 is installed by XCode.

I was having trouble understanding the scenario you seem to have in mind because it never occurred to me that someone would try to run Python without doing an install from python.org as I explicitly recommend.

If someone does install a version of Python from python.org, it puts the bin folder for that version first on PATH via this line in .zprofile:

PATH="/Library/Frameworks/Python.framework/Versions/3.11/bin:${PATH}"

It also puts a symlink for python3 and pip3 into the `/usr/local/bin` folder that comes ahead of `/usr/bin`.

So if the user runs

`pip3 install ...`

it will not find the version in `/usr/bin` because there will be two other directories ahead of it on the path that have an instance of `pip3`.

As an aside, if they do the improbable and run something like

`/usr/bin/pip3 install ...`

or if they do not have any Python from python.org installed and run

`pip3 install`

what they will end up with is a user-install that puts libraries under their `~/Library` directory because (at least on an Apple Silicon mac) pip can't write to `/usr/bin`. This fallback to a user-install is confusing to people who encounter it, but it is very different from "installing to the system python."

To summarize, it is exceedingly unlikely that a student who is not comfortable running commands from the terminal is going make the mistake you seem to be worried about and end up with libraries in the user-install location:

1. They do not install an official Python even though that is exactly what I recommend.

2. They do install XCode or XCode Command Line tools, then try to use `pip3 install ...`