specs:
macOs BigSur
Iterm2 with ohmyzsh
preinstalled with python2.7.16 & python 3.9.5
Problem :
i upgraded pip without pyenv , so now both pip and pip3 refer to python 3.9.5
i made an alias for python 3.9.5 to be default in .zshrc file
i also used pip to install flask
Questions :
Do i donwgrade pip for python2.7.16?
Or re install python2.7.16 with its pip?
i know i must have used pyenv but; is it possible now ? after 2 versions already installed?
* system (set by /Users/johnDoe/.pyenv/version) ➜ ~ python2 --version Python 2.7.16 ➜ ~ python3 --version Python 3.9.5 ➜ ~ pip --version pip 21.1.2 from /usr/local/lib/python3.9/site-packages/pip (python 3.9) ➜ ~ pip3 --version pip 21.1.2 from /usr/local/lib/python3.9/site-packages/pip (python 3.9) ➜ ~ pip freeze click==8.0.1 Flask==2.0.1 itsdangerous==2.0.1 Jinja2==3.0.1 MarkupSafe==2.0.1 Werkzeug==2.0.1 ➜ ~ where python python: aliased to /usr/local/bin/python3 /usr/bin/python ➜ ~ where python3 /usr/local/bin/python3 /usr/local/bin/python3 /usr/bin/python3 ➜ ~ where pip pip: aliased to /usr/local/bin/pip3 /usr/local/bin/pip /usr/local/bin/pip ➜ ~ where pip3 /usr/local/bin/pip3 /usr/local/bin/pip3 /usr/bin/pip3 ➜ ~ which pip pip: aliased to /usr/local/bin/pip3 ➜ ~ which pip3 /usr/local/bin/pip3 ➜ ~ which python python: aliased to /usr/local/bin/python3 ➜ ~ which python3 /usr/local/bin/python3 ➜ ~ which python2 /usr/bin/python2 ➜ ~ where flask /usr/local/bin/flask /usr/local/bin/flask ➜ ~ which flask /usr/local/bin/flask
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Answer
You should downgrade the pip package of your Python 2 installation as Pip 21.0 dropped supported for Python 2.
For some reason, the pip command on your system refers to the Python 3 installation. One would think there’d be two commands, pip2 and pip3, just as for the Python interpreter.
Therefore, run the following command to downgrade Pip for Python 2 to the last supported version:
python2 -m pip install "pip<21.0"
Here pip is called “as a module” via python2. This makes sure it uses the Pip package manager of the Python 2 installation, and not the (separate) one for Python 3.