Using both Python 2 x and Python 3 x in IPython Notebook

Question

I use IPython notebooks and would like to be able to select to create a 2 x or 3 x python notebook in IPython   I initially had Anaconda   With Anaconda a global environment variable had to be changed to select what version of python you want and then IPython could be started   This is not what I was looking for so I uninstalled Anaconda and now have set up my own installation using MacPorts and PiP   It seems that I still have to use  port select --set python  lt python version gt     to toggle between python 2 x and 3 x  which is no better than the anaconda solution   Is there a way to select what version of python you want to use after you start an IPython notebook  preferably with my current MacPorts build

User · Answer

From my Linux installation I did   sudo ipython2 kernelspec install-self  And now my python 2 is back on the list   Reference   http   ipython readthedocs org en latest install kernel install html    UPDATE   The method above is now deprecated and will be dropped in the future  The new method should be   sudo ipython2 kernel install

User · Answer

A solution is available that allows me to keep my MacPorts installation by configuring the Ipython kernelspec   Requirements    MacPorts is installed in the usual  opt directory python 2 7 is installed through macports python 3 4 is installed through macports Ipython is installed for python 2 7 Ipython is installed for python 3 4   For python 2 x     cd  opt local Library Frameworks Python framework Versions 2 7 bin   sudo   ipython kernelspec install-self   For python 3 x     cd  opt local Library Frameworks Python framework Versions 3 4 bin   sudo   ipython kernelspec install-self   Now you can open an Ipython notebook and then choose a python 2 x or a python 3 x notebook

User · Answer

I looked at this excellent info and then wondered  since    i have python2  python3 and IPython all installed  i have PyCharm installed  PyCharm uses IPython for its Python Console    if PyCharm would use    IPython-py2 when Menu File Settings Project Project Interpreter    py2  AND IPython-py3 when Menu File Settings Project Project Interpreter    py3   ANSWER  Yes   P S  i have Python Launcher for Windows installed as well

User · Answer

With a current version of the Notebook Jupyter  you can create a Python3 kernel  After starting a new notebook application from the command line with Python 2 you should see an entry    Python 3    in the dropdown menu    New     This gives you a notebook that uses Python 3  So you can have two notebooks side-by-side with different Python versions   The Details   Create this directory  mkdir -p    ipython kernels python3 Create this file    ipython kernels python3 kernel json with this content          display name    IPython  Python 3          language    python         argv              python3             -c    from IPython kernel zmq kernelapp import main  main               -f     connection file                codemirror mode              version   2            name    ipython           Restart the notebook server  Select    Python 3     from the dropdown menu    New    Work with a Python 3 Notebook Select    Python 2     from the dropdown menu    New    Work with a Python 2 Notebook

User · Answer

Use sudo pip3 install jupyter for installing jupyter for python3 and sudo pip install jupyter for installing jupyter notebook for python2  Then  you can call ipython kernel install command to enable both types of notebook to choose from in jupyter notebook

User · Answer

If you are running anaconda in virtual environment  And when you create a new notebook but i s not showing to select the virtual environment kernel  Then you have to set it into the ipykernel using the following command     pip install --user ipykernel   python -m ipykernel install --user --name test2

User · Answer

If you   re running Jupyter on Python 3  you can set up a Python 2 kernel like this   python2 -m pip install ipykernel  python2 -m ipykernel install --user   http   ipython readthedocs io en stable install kernel install html

User · Answer

Under Windows 7 I had anaconda and anaconda3 installed  I went into  Users me anaconda Scripts and executed   sudo   ipython kernelspec install-self   then I went into  Users me anaconda3 Scripts and executed  sudo   ipython kernel install    I got  jupyter kernelspec install-self is DEPRECATED as of 4 0  You probably want  ipython kernel install  to install the IPython kernelspec    After starting jupyter notebook  in anaconda3  I got a neat dropdown menu in the upper right corner under  New  letting me choose between Python 2 odr Python 3 kernels

User · Answer

Following are the steps to add the python2 kernel to jupyter notebook    open a terminal and create a new python 2 environment  conda create -n py27 python 2 7  activate the environment  Linux source activate py27 or windows activate py27  install the kernel in the env  conda install notebook ipykernel  install the kernel for outside the env  ipython kernel install --user  close the env  source deactivate  Although a late answer hope someone finds it useful  p

User · Answer

These instructions explain how to install a python2 and python3 kernel in separate virtual environments for non-anaconda users  If you are using anaconda  please find my other answer for a solution directly tailored to anaconda    I assume that you already have jupyter notebook installed     First make sure that you have a python2 and a python3 interpreter with pip available   On ubuntu you would install these by   sudo apt-get install python-dev python3-dev python-pip python3-pip   Next prepare and register the kernel environments  python -m pip install virtualenv --user    configure python2 kernel python -m virtualenv -p python2   py2 kernel source   py2 kernel bin activate python -m pip install ipykernel ipython kernel install --name py2 --user deactivate    configure python3 kernel python -m virtualenv -p python3   py3 kernel source   py3 kernel bin activate python -m pip install ipykernel ipython kernel install --name py3 --user deactivate   To make things easier  you may want to add shell aliases for the activation command to your shell config file  Depending on the system and shell you use  this can be e g     bashrc     bash profile or    zshrc  alias kernel2  source   py2 kernel bin activate  alias kernel3  source   py3 kernel bin activate    After restarting your shell  you can now install new packages after activating the environment you want to use   kernel2 python -m pip install  lt pkg-name gt  deactivate   or  kernel3 python -m pip install  lt pkg-name gt  deactivate

User · Answer

The idea here is to install multiple ipython kernels  Here are instructions for anaconda  If you are not using anaconda  I recently added instructions using pure virtualenvs   Anaconda    4 1 0  Since version 4 1 0  anaconda includes a special package nb conda kernels that detects conda environments with notebook kernels and automatically registers them  This makes using a new python version as easy as creating new conda environments   conda create -n py27 python 2 7 ipykernel conda create -n py36 python 3 6 ipykernel   After a restart of jupyter notebook  the new kernels are available over the graphical interface  Please note that new packages have to be explicitly installed into the new environments  The Managing environments section in conda s docs provides further information   Manually registering kernels  Users who do not want to use nb conda kernels or still use older versions of anaconda can use the following steps to manually register ipython kernels   configure the python2 7 environment   conda create -n py27 python 2 7 conda activate py27 conda install notebook ipykernel ipython kernel install --user   configure the python3 6 environment   conda create -n py36 python 3 6 conda activate py36 conda install notebook ipykernel ipython kernel install --user   After that you should be able to choose between python2 and python3 when creating a new notebook in the interface   Additionally you can pass the --name and --display-name options to ipython kernel install if you want to change the names of your kernels  See ipython kernel install --help for more informations

[python] Using both Python 2.x and Python 3.x in IPython Notebook

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