Python2 vs Python 3

The print, in Python 3, is a function not a statement. Now, keyword arguments are replacing most of the special syntax of the old print statement.

Python 2: print 'a=',a
Python 3: print('a=',a)
Python 2: print a, # Trailing comma suppresses newline
Python 3: print(a, end=" ") # Appends a space instead of a newline
Python 2:>>> print # newline>>> 
Python 3:>>> print
>>> print() # need function call>>> 

The function to get input from the keyboard is raw_input() in Python2, however, in Python 3, the input()raw_input() is not accepted in Python 3:

# Python 2:>>> id = raw_input('type your id : ')
type your id : 10095>>> id = input('type your id : ')
type your id : 20077
# Python 3:>>> id = raw_input('type your id : ')
Traceback (most recent call last):
 File "", line 1, in 
NameError: name 'raw_input' is not defined>>> id = input('type your id : ')
type your id : 30055

range() now behaves like xrange() used to behave. The xrange() no longer exists.

# Python 2>>> L2 = range(5)>>> L2
[0, 1, 2, 3, 4]
# Python 3>>> L3 = range(5)>>> L3
range(0, 5)>>> L4 = list(range(5))>>> L4
[0, 1, 2, 3, 4]
# Python 2>>> (a, *b) = range(5)
 File "", line 1
 (a, *b) = range(5)
 ^
SyntaxError: invalid syntax>>> 

Now the range() has "Extended Iterable Unpacking" feature. We write things like a, b, *rest = some_sequence, and even *rest, a = stuff. The rest object is always a (possibly empty) list; the right-hand side may be any iterable.

# Python 3>>> (a, *b) = range(5)>>> a
0>>> b
[1, 2, 3, 4]>>> (*c, d) = range(5)>>> c
[0, 1, 2, 3]>>> d
4>>> (e, *f, g) = range(5)>>> e
0>>> f
[1, 2, 3]>>> g
4

In Python 2, doing division int/int results in an floored integer.

# Python 2>>> 1/2
0
# Python 3>>> 1/2
0.5