How to install and run virtualenv on MacOS correctly

Question

Hi I'm a beginner of python, I don't remember when and how I installed python3.8 on my Macbook air, only knew the installed path:

% which python
/usr/bin/python
% which python3
/usr/local/bin/python3

The pip command cannot not be found but pip3 is ok. Today I want to install virtaulenv:

% sudo -H pip3 install virtualenv
WARNING: Ignoring invalid distribution - (/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages)
Successfully installed virtualenv-20.6.0

I can use "pip3 show virtualenv" to know the info:

% pip3 show virtualenv
Name: virtualenv
Version: 20.6.0
Summary: Virtual Python Environment builder
Home-page: https://virtualenv.pypa.io/
Author: Bernat Gabor
Author-email: [email protected]
License: MIT
Location: /Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages
Requires: six, platformdirs, backports.entry-points-selectable, distlib, filelock
Required-by:

But when I use "virtualenv" I got command not found message then I "pip3 uninstall" it. I searched for this and got a tip to use "easy_install" to install virtualenv. After installed I can execute the command, but got some error message:

% virtualenv                     
Traceback (most recent call last):
  File "/usr/local/bin/virtualenv", line 6, in <module>
    from pkg_resources import load_entry_point
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources/__init__.py", line 3241, in <module>
    @_call_aside
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources/__init__.py", line 3225, in _call_aside
    f(*args, **kwargs)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources/__init__.py", line 3254, in _initialize_master_working_set
    working_set = WorkingSet._build_master()
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources/__init__.py", line 583, in _build_master
    ws.require(__requires__)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources/__init__.py", line 900, in require
    needed = self.resolve(parse_requirements(requirements))
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources/__init__.py", line 786, in resolve
    raise DistributionNotFound(req, requirers)
pkg_resources.DistributionNotFound: The 'importlib-resources>=1.0' distribution was not found and is required by virtualenv

It seems doesn't work and I try the "sudo pip3 uninstall virtualenv" to uninstall it successfully, but it seems not really be removed:

% which virtualenv              
/usr/local/bin/virtualenv

I have no idea about this, could you help me? I just want to run virtualenv normally and create flask project ...

PS. I can "sudo pip3 install flask" and "pip3 show flask" but still cannot run flask cammand (command not found), what should I do?

Thanks a lot!

Adkinson

Answer 1

try being explicit in the version of python you are using and install using -m pip instead

python3 -m pip install virtualenv
python3 -m virtualenv venv # create a new venv in ./venv
source ./venv/bin/activate # activate your new venv

often times the pip/pip3 just isnt pointing at the same python version you think you are using... by using this technique you are sure to be using the correct python and pip

Boardwalk

Answer 2

In case you are doing this only because you need to install packages you can always use homebrew:

brew install python3

brew install pipx

pipx install package-name

Karole