Install Python 3.x on Mac OS X

The pre-installed python in Mac OS X Yosemite is Python 2.x.
(not sure the pre-installed version of later version: EI Caption and Seirra)

To use Python 3.x, we have to install it by ourself. Thanks for Internet and may contributors on it, there are many instructions about how to install Python 3.x on Mac.

I choose one of them below and made some note for the problems that encountered during installation.


Instructions to Install Python on Mac OX

How to upgrade your mac to Python3 (macobserver.com)

* By default, the installer will add Python3 path to .profile but it doesn't add path to .cshrc. Therefore, for csh users, your should add Python3 to the search path manually. Here are examples:

setenv PATH "/Library/Frameworks/Python.framework/Versions/3.5/bin:$PATH"

The most quick ways is copy setenv statement from .profile and modify it for csh syntax.

Download Python: 

Download Python (python.org)

Actually, there are many topic talking about install Python 3.x with package management (?). However, these method usually take many steps to finish this job by user itself.
As a newbie to Mac OS and Python,  selecting a simple way to build up a basic environment for using Python is a way to lower the learning curve and bring focus on Python effectively.
Hope I have made the right choose :D .