How to know which Python is running in Jupyter notebook?

from platform import python_versionprint(python_version())

This will give you the exact version of python running your script. eg output:

3.6.5

import syssys.executable

will give you the interpreter. You can select the interpreter you want when you create a new notebook. Make sure the path to your anaconda interpreter is added to your path (somewhere in your bashrc/bash_profile most likely).

For example I used to have the following line in my .bash_profile, that I added manually :

export PATH="$HOME/anaconda3/bin:$PATH"

EDIT: As mentioned in a comment, this is not the proper way to add anaconda to the path. Quoting Anaconda's doc, this should be done instead after install, using conda init:

Should I add Anaconda to the macOS or Linux PATH?

We do not recommend adding Anaconda to the PATH manually. During installation, you will be asked “Do you wish the installer to initialize Anaconda3 by running conda init?” We recommend “yes”. If you enter “no”, then conda will not modify your shell scripts at all. In order to initialize after the installation process is done, first run source <path to conda>/bin/activate and then run conda init

import sysprint(sys.executable)print(sys.version)print(sys.version_info)

Seen below :- output when i run JupyterNotebook outside a CONDA venv

/home/dhankar/anaconda2/bin/python2.7.12 |Anaconda 4.2.0 (64-bit)| (default, Jul  2 2016, 17:42:40) [GCC 4.4.7 20120313 (Red Hat 4.4.7-1)]sys.version_info(major=2, minor=7, micro=12, releaselevel='final', serial=0) 

Seen below when i run same JupyterNoteBook within a CONDA Venv created with command --

conda create -n py35 python=3.5 ## Here - py35 , is name of my VENV

in my Jupyter Notebook it prints :-

/home/dhankar/anaconda2/envs/py35/bin/python3.5.2 |Continuum Analytics, Inc.| (default, Jul  2 2016, 17:53:06) [GCC 4.4.7 20120313 (Red Hat 4.4.7-1)]sys.version_info(major=3, minor=5, micro=2, releaselevel='final', serial=0)

also if you already have various VENV's created with different versions of Python you switch to the desired Kernel by choosing KERNEL >> CHANGE KERNEL from within the JupyterNotebook menu...JupyterNotebookScreencapture

Also to install ipykernel within an existing CONDA Virtual Environment -

http://ipython.readthedocs.io/en/stable/install/kernel_install.html#kernels-for-different-environments

Source --- https://github.com/jupyter/notebook/issues/1524

 $ /path/to/python -m  ipykernel install --help usage: ipython-kernel-install [-h] [--user] [--name NAME]                          [--display-name DISPLAY_NAME]                          [--profile PROFILE] [--prefix PREFIX]                          [--sys-prefix]

Install the IPython kernel spec.

optional arguments:-h, --help show this help message and exit--user Install for the current user instead of system-wide--name NAME Specify a name for the kernelspec. This is needed tohave multiple IPython kernels at the same time.--display-name DISPLAY_NAMESpecify the display name for the kernelspec. This ishelpful when you have multiple IPython kernels.--profile PROFILE Specify an IPython profile to load. This can be usedto create custom versions of the kernel.--prefix PREFIX Specify an install prefix for the kernelspec. This isneeded to install into a non-default location, such asa conda/virtual-env.--sys-prefix Install to Python's sys.prefix. Shorthand for--prefix='/Users/bussonniermatthias/anaconda'. For usein conda/virtual-envs.