1, first according to https://www.pyimagesearch.com/2017/09/25/configuring-ubuntu-for-deep-learning-with-python/ The content in the address is configured VIRTUALEVN the virtual environment,
Assuming that the current virtual environment is DL4CV, start it first: Workon DL4CV, type: $: Python, and you'll see the current virtual environment as python3.6.1, or Python3.
2, enter $: Jupyter notebook, will start the browser Jupyter, after launch, click on the right icon New, if only Python2, then first exit the Jupyter
3, under DL4CV virtual, installation Jupyter:pip install Ipython and pip install Jupyter
4. Wait for the installation to complete, by command: $: python-m ipykernel Install--user Add the Python3 of the current environment to the Jupyter.
5. At this point, type again: $: Jupyter notebook, will start the browser Jupyter, after launch, click on the right icon New, you will be able to see both Python2 and Python3.
Configuring Python3 in Jupyter