From which version of python should I learning it 2.7 or 3.4

Answer 1

for window 7 2.7 or window ten 3.4 is best

Answer 2

I would recommend 3.4. Python 2.7 is fading away and pretty soon there will be no support for 2.7. But I don't recommend the latest version like 3.6 because some of the tools don't support yet. For example, py2exe does not support Python 3.6. I recommend 3.4.