keeping python 3 up to date on a mac

I personally use Homebrew, which is a very nice package manager. If you want to give this a try, first of all make sure you have the XCode Command Line Tools installed on your Mac. Then install Homebrew by typing

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

in the Terminal. Homebrew will place its "Cellar" (the set of all the packages you installed with Homebrew) in /usr/local/Cellar.

Now, about Python 3, once Homebrew is installed simply type

brew install python3

and there we go. You have Python3 installed on your Mac.

Notes:

• this version will automatically take place instead of the OS X version (if it doesn't, just run brew link python3 - this will symlink python3 into /usr/local/bin/)
• to update python run brew update in the Terminal (this will update Homebrew) and then brew upgrade python3 if a new version of python3 is found by the command brew update
• at the end you can run brew cleanup python3 to remove every old version
• with this fancy package manager, you can also take care of R

Use Homebrew :)

brew install python3

Hombrew installs everything into /usr/local/Cellar and creates symbolic links for applications in /usr/local/bin. It will not touch anything else in the system. It comes with the brew cleanup command, which removes unused or outdated applications automatically.

To update it:

brew update
brew upgrade python3

It will automatically link to the newest version after an upgrade and brew clean removes any remains of the previous version.