Which is best? Python 1x, 2x or 3x ?

Answer 1

It's better to learn Python 3

Answer 2

Python 3x is backward compatible with Python 2x and python 1x.
But Python 1x is not compatible with Python 2x and Python 3x but Python 1x and Python 2x can be transformed to Python 3x.
So why do you have to do your code in Python 1x or 2x and then change it to Python 3x in addition Python 1x and 2x have less functions and modules than 3x.
So I recommend to learn Python 3x

Answer 3

As Python Software Foundation (PSF) would discontinue its support for 2.x in 2020 as it did with 1.x previously... So, its a plus point for 3.x as well see major new features in 3.x by visiting https://www.python.org/downloads/release/python-352/ i.e. official Python site... Hope it would assists you :)