Which is good to learn.Python 2.7 or Python 3

Answer 1

I'd say python 3, since it's newer.

Answer 2

They are pretty similar, either is good to start. Recent tutorials may consider Python 3 but there are a lot of resource available on Python 2, starting with the free e-book "Think into Python" (plus Python 2 is still the default in many Linux distributions). Apps and online classes nowadays probably prefer Python 3 (Sololearn, Datacamp, and so on). If you write code for Python 2.7 there is a tool to convert it to Python 3 (named 2to3 or something like that).

Some differences between Python 2.7 and 3 that you are likely to run into when you begin coding.
1. Python 2.7 has a unique division operator / for both integer and floating division (1/2 is 0 while 1.0/2, 1/2., 1./2.0, ... is 0.5) while Python 3 has / for floating division and // for integer division.
2. In Python 2 print is a statement, while in Python 3 it is a function. As a function you could, e.g, replace print with another function and in general you are more flexible. Pro tip: if you want to write code compatible with both Python 2 and 3 always put round brackets around your argument, as in print(x). They are useless (but harmless) in Python 2 and required in Python 3.
3. In Python 3 the range () function creates a generator like the xrange () function does in Python 2 (whilst range () creates a list).

Answer 3

If you just started with learning Python, you should go with Python3, because it is future proof and you already got many useful resources. Python2 will get updates until 2020.