How to force google colab to run in particular python version

Question

I have a code which works in python3.5 but will throw errors in python>3.5 but with !python --version in google colab return python 3.6.9, is there any way I can force google colab to use 3.5. I found some solutions in Stackoverflow which asked me to use local run time which won't be useful for me because I don't have enough computational resources in my local machine.

Answer 1

There is a way to use any version of python you want, let's say python3.5, without having to run a kernel locally or going through an ngrok proxy.

Download the colab notebook. Open a text editor to change the kernel specification to:

"kernelspec": {
  "name": "py35",
  "display_name": "Python 3.5"
}

This is the same trick as the one used with Javascript, Java, and Golang.

Then upload the edited notebook to Google Drive. Open the notebook in Google Colab. It cannot find the py35 kernel, so it use normal python3 kernel. You need to install a python 3.5, the google-colab package and the ipykernel under the name you defined above: "py35":

!apt-get install python3.5
!curl -O https://bootstrap.pypa.io/pip/3.5/get-pip.py
!python3.5 get-pip.py
!python3.5 -m pip install jupyter google-colab
!python3.5 -m ipykernel install --name "py35" --user

Reload the page, and test the version is correct:

import sys
print("User Current Version:-", sys.version)