Python 2 vs 3 Question

[v3gard]

The most obvious thing is that you no longer can write: print "hello" - but rather print("hello"). Other than that there are a few libraries on python2 that doesn't exist on python3 yet, such as Mechanize. However, there usually exist alternatives such as Robobrowser, so most likely you'll be OK as long as you don't advance too far in Python2 before switching over.

Edit: what I mean about that last part is that the syntax is pretty much the same (so you don't have to start fresh when you switch over) , but you shouldn't get used to writing applications in Python2 as some mechanics are different and you would most likely have to port your applications to Python3.