Problem installing package for a specific version of Python

Question

I need to run some code in Python 2.7.x. I have Python 2.7.16, Python 3.9.6, and both pip and pip3 (which point to the same place) as shown below:

% python --version
Python 2.7.16
% python3 --version
Python 3.9.6
% pip --version
pip 21.1.3 from /usr/local/lib/python3.9/site-packages/pip (python 3.9)
% pip3 --version
pip 21.1.3 from /usr/local/lib/python3.9/site-packages/pip (python 3.9)

The code I am trying to run requires me to run python setup.py build but this yields the error:

Traceback (most recent call last):
  File "setup.py", line 25, in <module>
    from Cython.Distutils import build_ext
ImportError: No module named Cython.Distutils

So, installing cython gives me:

% pip install cython 
Requirement already satisfied: cython in /usr/local/lib/python3.9/site-packages (0.29.24)

Notice this points to Python 3, not Python 2.7. So I try to run python -m pip install cython but that yields the following error:

Traceback (most recent call last):
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/runpy.py", line 174, in _run_module_as_main
"__main__", fname, loader, pkg_name)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/runpy.py", line 72, in _run_code
    exec code in run_globals
  File "/Library/Python/2.7/site-packages/pip-21.0-py2.7.egg/pip/__main__.py", line 21, in <module>
    from pip._internal.cli.main import main as _main
  File "/Library/Python/2.7/site-packages/pip-21.0-py2.7.egg/pip/_internal/cli/main.py", line 60
    sys.stderr.write(f"ERROR: {exc}")
                                   ^
SyntaxError: invalid syntax

Not sure what is going on. I recently updated Xcode, so that shouldn't be the issue.

You're right: https://pip.pypa.io/en/latest/development/release-process/#python-2-support — Erik M, Jul 23 '21 at 07:31
Looks like that syntax error could be caused by python 2 attempting to run code containing an F-string? F-strings were obviously introduced in python 3.6 — Alex Waygood, Jul 23 '21 at 07:32
https://stackoverflow.com/search?q=%5Bpip%5D+sys.stderr.write%28f%22ERROR%3A+%7Bexc%7D%22%29 — phd, Jul 23 '21 at 11:57

score 0 · Answer 1 · answered Jul 23 '21 at 07:41

0

Based on this

% python --version
Python 2.7.16
% python3 --version
Python 3.9.6
% pip --version
pip 21.1.3 from /usr/local/lib/python3.9/site-packages/pip (python 3.9)
% pip3 --version
pip 21.1.3 from /usr/local/lib/python3.9/site-packages/pip (python 3.9)

and this python setup.py build

seems like you should use python3 setup.py build because f-strings are not a part of python 2

answered Jul 23 '21 at 07:41

T.M15

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Thanks. The code I am running requires Python 2.7.x. I found that the following worked: `sudo easy_install pip==20.3.4`. – Erik M Jul 23 '21 at 07:43

Problem installing package for a specific version of Python

1 Answers1