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Table of contents
1.
Introduction
2.
What is Python 2
3.
What is Python 3
4.
Differences between Python 2 and Python 3
4.1.
Print keyword/function
4.2.
Taking Input
4.3.
Division Operation
4.4.
Not equal to operator.
4.5.
Unicode
4.6.
Error Handling
4.7.
xrange function
5.
FAQs
6.
Key Takeaways
Last Updated: Mar 27, 2024

Python 2 vs. Python 3

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Introduction

The Python programming language has received a lot of attention over the years. It is one of the programming languages that has elevated technology to new heights. Python is one of the easiest programming languages to learn. Hence it is often taught as an introductory language to first-year college students. It has found its usage in many different fields such as Machine learning, Artificial Intelligence, Web/App development, Data Science, etc. 

Even though it is not old, it has evolved as an efficient and powerful language due to its open-source nature and community support. Python has evolved through several versions, the most current of which is Python 3. Even though they are both merely different variants of the same programming language, they have significant differences.

Read more,   reverse a string in python

What is Python 2

Python 2,  introduced in the year 2000, the main goal was to make code development more manageable and more efficient than previous versions and make it easy to learn for the general public.

Python 2 implemented technical details of the Python Enhancement Proposal (PEP). But after the arrival of Python 3, Python 2 lagged in the industry. The last version of Python 2 was Python 2.7, and it has been discontinued since 2020. 

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What is Python 3

Python 3, released in December 2008, is the most recent version of Python. This version of Python was released to fix the significant problems in the old version, mainly redundancy. It is backward incompatible, meaning that the newer version does not support the code written in the older version. 

Some Python 3 features have been backported to Python 2 versions to simplify the Python 3 migration process.

Also see, Swapcase in Python, And  Convert String to List Python

Differences between Python 2 and Python 3

Print keyword/function

In Python 2, the “print” is treated as a statement. Hence it is not necessary to wrap parenthesis around the text.

# python 2
print 'Hello World!'

In contrast to Python 2, it is treated as a function in Python 3. Hence it is necessary to pass the text you want to print in the function parentheses, or else you will get a syntax error.

# python 3
print('Hello World!')

Taking Input

In Python 2, we would have to use raw_input() to take input from the user.

var = raw_input("Enter the value")

In Python 3, we use input() to take the input from the user. 

var = input("Enter the value")

The main difference between both the functions is that while raw_input() only returns a string, input() instead can return a python type like list, tuple, string, int, etc.

Division Operation

In Python 2, the result of the division operation was always an integer nearest to the actual value.

# python 2
6/5
>> 1

In Python 3, the result of the division operation is always a float value.

# python 3
6/5
>> 1.2

Not equal to operator.

In Python 2, not equals to operator used to be <>

# python 2
var = (1 <> 2)

In Python 3, it was replaced by !=. 

# python 3
var = (1 != 2)

Unicode

In all modern software and information technology protocols, the Unicode encoding standard serves as the foundation for the processing, storing, and interpreting text data in any language. Unicode strings are more versatile than ASCII strings because they can store letters from other languages, as well as emoji and ordinary Roman letters and digits. Python 3 automatically stores Unicode strings, but Python 2 needs you to designate a string with a "u" if you want it to be stored as Unicode. Python 2 stores strings in ASCII form as default.

# python 2 
type('abcd')
>> <type 'str'>
type(b'abcd')
>> <type 'str'>
type(u'abcd')
>> <type 'unicode'>

# python 3 
type('abcd')
>> <type 'str'>
type(b'abcd')
>> <type 'bytes'>
type(u'abcd')
>> <type 'str'>
# in Python 3, str and unicode are same 

Error Handling

There is a minor difference in the syntax between both versions. Instead of comma (‘,’) in Python 2, the ‘as’ keyword is required in Python 3.

# python 2
try :
try_block
except Error_name, err:
print 'Error :', err
# python 3
try :
try_block
except Error_name as err:
print ('Error :', err)

xrange function

The range function returns a list in Python 2, e.g., range(5) will return [0, 1, 2, 3, 4], while the xrange function will return a xrange iterator object. We prefer the range function over the xrange function when iterating over the same range several times since range() returns a static list. The xrange function does not support list techniques such as slicing. The advantage of the xrange function is that it saves memory when the range to iterate is large.

# Python 2
for i in xrange(3):
print(i)
>> 0 
>> 1
>> 2

The xrange function does not exist in Python 3, and the range function of Python 3 is the same as the xrange function of Python 2. 

# Python 3
for i in range(3):
print(i)
>> 0 
>> 1
>> 2

 

You can also read about the Multilevel Inheritance in Python.

Also see, How to Check Python Version in CMD

FAQs

  1. Which version of Python is faster?
    Python 3 is faster than Python 2 in most cases. 
     
  2. Which version of Python has easier syntax?
    The syntax of Python 3 is much easier than the syntax of Python 2. 
     
  3. Which version of Python is better to use?
    Python 3 is far more readable, understandable, and widely used than Python 2. Python 2 has run out of steam, and one should only study Python 2 if there is legacy Python 2 code or if a company requires the developer to move Python 2 code to Python 3.

Key Takeaways

Congratulations on making it this far.

In this blog, we got introduced to both versions of Python. We also studied where both versions differ and in what aspect they differ. 

If you want to take your learnings to next level, you can visit and read our library of curated blogs by clicking here

Learning never stops, and there is a lot more to learn. Happy Learning!!

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