Important differences between Python 2.x and Python 3.x with examples

Last Updated : 20 Sep, 2025

In this article, we will explore some important differences between Python 2.x and Python 3.x with the help of examples, focusing on the following libraries and modules.

  • Division operator
  • print function
  • Unicode
  • xrange
  • Error Handling
  • _future_ module

1. Python Division operator

  • In Python 2.x: dividing two integers performs floor division (discards decimals).
  • In Python 3.x: dividing two integers performs true division (keeps decimals).
Python 
print 7 / 5             
print -7 / 5            

print(7 / 5)           
print(-7 / 5)

Output in 2.x:

1
-2

Output in 3.x:

1.4
-1.4

2. Print Function in Python

  • In Python 2.x: print is a statement (no brackets needed).
  • In Python 3.x: print is a function, so parentheses are required.
Python 
# Python 2.x
print 'Hello, Geeks'        # print is a statement
print('This works too')     # works because it's treated like a function call

# Python 3.x
print('Hello, Geeks')       # print is a function (this is the only correct way)

Output in Python 2.x:
Hello, Geeks
This works too

Output in Python 3.x:
Hello, Geeks

3. Unicode In Python

  • Python 2.x: Strings are ASCII by default, unicode must be defined separately.
  • Python 3.x: Strings are Unicode by default.
Python 
print(type('default string'))
print(type(b'string with b'))


Output in Python 2.x:

<type 'str'>
<type 'str'>

Output in Python 3.x:

<class 'str'>
<class 'bytes'>

 4. xrange() vs range()

Python 2.x:

  • range() returns a list.
  • xrange() returns a generator (saves memory).

Python 3.x:

  • xrange() is removed.
  • range() behaves like Python 2’s xrange.
Python 
# Python 2.x
for x in xrange(1, 5):
    print(x),

for x in range(1, 5):
    print(x),

Output in Python 2.x:

1 2 3 4 1 2 3 4

Output in Python 3.x:

NameError: name 'xrange' is not defined

5. Error Handling

  • Python 2.x: Uses a comma to bind the exception.
  • Python 3.x: Uses as keyword (comma syntax no longer works).
Python 
# Python 2.x
try:
    x = not_defined
except NameError, err:
    print err, 'Error Caused'

Output in Python 2.x:

name 'not_defined' is not defined Error Caused

Output in Python 3.x:

SyntaxError: invalid syntax

Correct way (works in both):

try:
x = not_defined

except NameError as err:
print(err, 'Error Caused')

6. __future__ module in Python

__future__ module allows Python 2 code to adopt Python 3 features early, making migration easier.

Example 1: Division behavior

Python 
from __future__ import division

print(7 / 5)
print(-7 / 5)

Output (Python 2.x with future import):

1.4 
-1.4

Output (Python 3.x):

1.4
-1.4

Example 2: print as a function

Python 
from __future__ import print_function

print('GeeksforGeeks')

Output (Python 2.x with future import):

GeeksforGeeks

Output (Python 3.x with future import):

GeeksforGeeks

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