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OS X: How to link updated Python version (3.4 to 3.6)

I use Python 3.4 as 'python3' in terminal (Python 2.7 as 'python'). I recently installed Python 3.6 with Homebrew, but I cannot seem to replace the 3.4 version under 'python3' with 3.6.
I tried this, but I get an error and "Operation not permitted". I'm figuring I need to change a path somewhere, but I'm not sure which files to change.
EDIT: The answer to this question did not solve my problem, I'm fine keeping the default as it is. It does make me realise that maybe just changing the alias is enough, or it that not the appropriate way to go about this? (e.g. this)

To use your newly installed Python, follow ths link: python homebrew by default
Instead of changing the alias named "python3", you could use a virtualenv, that way, you can choose your Python version:
virtualenv -p python3.6 my_venv
source my_venv/bin/activate
python --version
# -> Python 3.6.1
Why do you use homebrew to install a new version of Python 3? You could have done directly from Mac OS X.

I ended up reinstalling, manually removing/reinstalling versions and packages, and then relinked the alias to the Python version I wanted to use. This setup seems to work for me so far.

How do I get python to import pandas?

I installed Python 3.5.1 from www.python.org. Everything works great. Except that you can't install pandas using pip (it needs visualstudio to compile, which I don't have). So I installed Anaconda (www.continuum.io/downloads). Now I can see pandas as part of the list of installed modules, but when I run python programs I still get:
ImportError: No module named 'pandas'
How do I set up my environment to use the modules from Anaconda?
Note: I have Anaconda's home directory and Library/bin on my path, as well as Python's home directory. I do not have PYTHONPATH or PYTHONHOME set, and I know I have the correct privileges to see everything.

I have successfully installed pandas for a Windows 32 bit version Python 3.4 with pre-complied code (no Visual Studio required) using the website:
http://www.lfd.uci.edu/~gohlke/pythonlibs/#pyyaml
There is link for Python 3.5 pre-complied code at this site as well, but I have not tested it.
Download the code you want to a directory on your machine.
Using your Windows CMD.exe, go to your python directory and enter:
Python -w pip install "YourDirectory/pandas-0.18.1-cp35-cp35m-win32.whl"
OR
Python -w pip install "YourDirectory/pandas-0.18.1-cp35-cp35m-win_amd64.whl
Choose the version based on the version of Python you have
have, 32 bit or 64 bit.
Good Luck!

Anaconda has included one version of Python with it. You have to change your system environment path with Anaconda's instead of the former one to avoid conflict. Also, if you want to make the whole process easy, it is recommended to use PyCharm, and it will ask you to choose the Python interpreter you want.

How do I change the kernel/python version for iPython?

I have installed iPython using pip in OS X 10.10, and it gave me the "ipython" and "ipython2" commands, which run great, but which use OS X's default python version 2.7.9. I downloaded and installed the latest release of Python3.4 and can load it with the command "python3," but cannot find a way to get iPython to use this version of python. The iPython Web site states the package can be used with python versions 3.3 and above, but I cannot find any instruction on how to change the default python version used.
So far I have found that the jupyter package for iPython has a kernel specification in /usr/local/share/jupyter/kernels/, which is just a folder called "python2" containing a json file that points to the system's python 2.7.6, but altering this to point to the new python3.4 installation does not work. My guess is this configuration is for the ipython notebook.
I've also tried the approach here: ipython reads wrong python version
In doing so I've duplicated the ipython2 command in /user/local/bin/ and edited it to use the python3 interpreter located at /Library/Frameworks/Python.framework/Versions/3.4/bin/python3, however, this gives me an error "ImportError: No module named 'IPython'," which suggests the python3 installation does not have ipython installed.
To tackle this, I've tried uninstalling ipython and reinstalling it using pip, but it just targets the system's Python 2.7 installation and does nothing for python3.
Does anyone know how to configure iPython to use a different python version, or even install a separate ipython installation for python3? Ultimately it would be nice to quickly switch back and forth depending on my needs.

I just found the answer. In essence, this stems from not understanding the python installation layout and how resources are separated between installed interpreters. It appears each python version will have its own repository of tools, and the current "pip" command I had installed on the system was mapped for use with python 2.7, so all libraries, tools, and other details it managed where available only to python 2.7. This included iPython.
I thought that installing python3 would make all these libraries available to the new interpreter by default, but it appears the system keeps them all separate (which makes sense). The main issue here was continuing to use "pip" which targeted the old installation, instead of the new "pip3" command included with python3. By using pip3 to reinstall iPython, I was able to get iPython3 installed properly.
Unfortunately this setup means needing to re-download other libraries, but that's not too difficult.
It might seem like a trivial issue in hindsight, but this had me completely stuck. I hope this helps someone else in this situation.

Brews Python 2.7.7 shows up as 2.7.5

I installed a fresh version of Python via
brew install python
Also
brew info python
tells me that it is at version 2.7.7.
I seem to remember that the python OSX Mavericks ships with is 2.5. So that
python --version
gives me 2.7.5 makes even less sense.
Also
which python
/usr/local/bin/python
should be the Homebrew version, correct?
I'm lost. Does anybody know, why my Python isn't version 2.7.7?

You have to explicitly tell brew that you want to switch to the version of python you just installed. To do that, type:
brew switch python 2.7.7
in your command line. This may not work if the version you installed is actually 2.7.7_2. In that case, just replace 2.7.7 with 2.7.7_2 above and run it again. Once this is done, you'll have to reload your environment to pick up the changes.

Python from my experience doesn't do an upgrade in the sense we would like it. Basically it will install python but not overwrite the old version. If you look in your main drive you will prolly see Python 2.7.7 and Python 2.7.5
usually in Windows its: C:\Python27
It doesn't really show the last digit (which from my knowledge refers to bugs fixed in the version), so it may overwrite unless it is an entirely new version. '
But I would check first if you have two files of Python. If you do then change your PATH variable environment to point to the latest and delete the old version.
That's my suggestion but I use Windows and pip install, so hopefully it is not too different.

Removing python and then re-installing on Mac OSX

I was wondering if anyone had tips on how to completely remove a python installation form Mac OSX (10.5.8) ... including virtual environments and its related binaries. Over the past few years I've completely messed up the installed site-packages, virtual-environments, etc. and the only way I can see to fix it is to just uninstall everything and re-install.
I'd like to completely re-do everything and use virtualenv, pip, etc. from the beginning.
On the other hand if anyone knows a way to do this without removing python and re-installing I'd be happy to here about it.
Thanks,
Will

Just for everyone else's reference. I found this in the Python documentation here:
Mac OS X 10.5 comes with Python 2.5.1 pre-installed by Apple. If you wish, you are invited to install the
most recent version of Python from the
Python website
(http://www.python.org). A current
“universal binary” build of Python,
which runs natively on the Mac’s new
Intel and legacy PPC CPU’s, is
available there.
What you get after installing is a
number of things:
* A MacPython 2.5 folder in your Applications folder. In here you find
IDLE, the development environment that
is a standard part of official Python
distributions; PythonLauncher, which
handles double-clicking Python scripts
from the Finder; and the “Build
Applet” tool, which allows you to
package Python scripts as standalone
applications on your system.
* A framework /Library/Frameworks/Python.framework,
which includes the Python executable
and libraries. The installer adds this
location to your shell path. To
uninstall MacPython, you can simply
remove these three things. A symlink
to the Python executable is placed in
/usr/local/bin/.
I removed these and the virtualenv directories. Then I re-installed everything and its working fine now.

You should be able to delete the packages you've installed from /Library/Python/2.*/site-packages/. I do not think any package installers will install by default to /System/Library, which should save you from needing to remove Python itself.
That said, you could also use virtualenv with --no-site-packages, and just ignore whatever packages you've installed system-wide without needing to remove them.