Here’s more about the difference between Python 2 and 3. Python for Windows, Linux/UNIX, Mac OS X, Other Want to help test development versions of Python?Pre-releases For most Unix systems, you must download and compile the source code.I wanted to know if there is a way to update a specific program from the command line, like will install latest available version, replacing the older one if needed.But with some software (among which is Python) the situation is somewhat different.Alternatively, if you’re a newbie to the language and/or your class instructor insists that you begin by learning 3.x, then you’ll need to install it on your Mac. (The 10.6 embedded in the file name means you need at least mac OS Snow Leopard to run it.It’s particularly easy to do because 1) There’s an mac OS installer package that does the work and 2) it includes a basic IDE, and 3) you can still run both versions, so there’s no penalty to installing 3.6.x. That means everything from 10.6 Snow Leopard up to and including 10.13 Sierra.)When you double-click this file, it will launch the package’s installer, and you’ll see this: There are several steps.
So in fact, fairly large part of the system easily run on, say, Python 2.7 — because incompatibilities exist.
Read more Note: Barry's key id A74B06BF is used to sign the Python 2.6.8 and 2.6.9 releases.