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