Want to select python3.9 ( installed and tested) but can only see default 3.8

Hi there
new to jupyter lab and itching to get started. I have installed python3.9 and tested it out from my linux mint 20 bash shell, it’s fine. BUT when I start a copy of jupter lab Version 4.0.5 I cannot see the python3.9 kernel. Just the 3.8 ( preferred) kernel which causes my code to fail as it needs 3.9

The python3.9 kernel does NOT show up in any of the drop downs or menu selections. I am running in a python venv so can I do something in that to make it show up? I can run python3.9 in the venv

Did I miss something in the config instructions?
thanks for ANY help

This should be caused by your linux system’s python3 or python still pointing to 3.8, you can use update-alternatives to point your system’s python3 to 3.9, and then you might get happy results.

# create python3 pointer selection for 3.8 
# you might want to check your python path first and modify the path params
$ sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.8 110

# create python3 pointer selection for 3.9
$ sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.9 100

# use the menu to select which python version to use when any commands/apps call python3
$ sudo update-alternatives --config python3

I’m puzzled? I was under the impression that I could select a kernel from a drop down list. I have python3.8 which shows up as you say. But I also have 3.9 which does not. I also have julia installed which also does not show up on the kernel selection list.

so my questions stands, how do I add kernels to the selection list please?

Did you install the Python 3.9 kernel?


I did not. I didn’t know I had to do this. Thank you for the really helpful link. I’ll do this next time as I just hacked around it using

 python3.9 -m venv test_jup

doesn’t help me with julia but that’s for another day. Thanks again. I’ll mark this as solved as it seems like something that should work.

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