Key Differences Between Python 2 and Python 3 – Python 2.x vs Python 3.x

From the time of its creation (1991) till the present, Python has traveled a very long road and published several versions. Python 3 is now in use and it was designed to address some of the problems of Python 2. Although Python 2 is virtually obsolete, some software professionals continue to use it because of some of its unique characteristics. Let’s use this blog to better grasp the differences between Python 2 and Python 3.

Python 2

As opposed to prior versions, Python 2’s advancement allowed programmers to simplify the writing of code. Python 2’s development made it feasible to implement the technical aspects of the Python Enhancement Proposal (PEP). The 2.x series of Python was retired in 2020 with Python 2.7 being the final release. Further information about Python 2 is provided by the following points:

• Python 2 was created with the primary goal of making programming simple and approachable for the average person who wants to learn a programming language.
• The developer of the Python programming language, Guido van Rossum, a Dutch programmer, also produced Python 2.0. Release day was October 16, 2000.
• It provided a number of significant new features, including list comprehensions, support for Unicode, and a cycle-detecting garbage collector for memory management.

What makes learning Python 2 important?

Despite being an outdated open-source version, Python 2 is still necessary in the following situations:

• You must work with configuration management technologies like puppet or ansible if you want to become a DevOps engineer. You must use both of these variants in this situation.
• You will need to learn how to use Python 2 if your company’s programming is developed in that language.
• Python 2 is your only choice if your development team is working on a project that depends on particular third-party libraries or software that you are unable to transfer to Python 3.

History of Python 2

Python 2.0 – October 16, 2000

Python 2.1 – April 17, 2001

Python 2.2 – December 21, 2001

Python 2.3 – July 29, 2003

Python 2.4 – November 30, 2004

Python 2.5 – September 19, 2006

Python 2.6 – October 1, 2008

Python 2.7-July 3, 2010

Python 3

A more recent version of the Python programming language is Python 3. Python 3 was primarily intended to address the issues that programmers were having with Python 2.

• Because it was impossible to execute the necessary modifications while maintaining full backward compatibility with the 2.x series, Python 3.0 was primarily created to address fundamental design issues in Python’s prior versions, 2.x series. Because of this, Python 3 was created.
• Guido van Rossum, a Dutch programmer best known for creating the Python programming language, created Python 3.
• Python came out in 2008. It was a significant update that is not entirely backward compatible with older iterations.

Why should you pick Python 3?

The following are the main considerations for utilizing Python 3.x:

• Python 3 supports contemporary techniques like AI, machine learning, and data science.
• A sizable community of Python developers supports Python 3. Seeking assistance is simple.
• Compared to prior versions, Python is simpler to learn.
• Offers Toolset and libraries that are strong
• Ability to coexist with various languages

History of Python 3

Python 3.0 – December 3, 2008

Python 3.1 – June 27, 2009

Python 3.2 – February 20, 2011

Python 3.3 – September 29, 2012

Python 3.4-March 16, 2014

Python 3.5 – September 13, 2015

Python 3.6- October 2016

Python 3.7- June 2018.

Comparison Between Python 2 and Python 3

Python 2 vs. Python 3 Example Code “Print Function”

Python 3

def main():

   print(“Hello World!”)

if __name__== “__main__”:

   main()

Python 2

def main():

  print “Hello World!”

if __name__== “__main__”:

  main()

Example Code: Unicode Strings

Python 2: 

import sys

——————————————

print ‘We are using Python version’, sys.version[:3]

print type(‘default string ‘)

print type(b’string with b ‘)   #bytes and default alike in python 2

print type(u’string with u’)    #python2 supports Unicode too

——————————————

Output:

——————————————

We are using Python version 2.7

<type ‘str’>

<type ‘str’>

<type ‘unicode’>

——————————————

Python 3:

import sys

——————————————

print(‘We are using Python version’, sys.version[:3])

print(type(‘default string ‘))  #unicode

print(type(b’string with b ‘))   #bytes and default both different in python 3

——————————————

Output:

——————————————

We are using Python version 3.8

<class ‘str’>

<class ‘bytes’>

——————————————

Example: Error Handling 

In Python 3, the term “as,” a new one, is added. Python 3 requires it, and if it is not provided, an error will be produced. Here is some sample code to help you understand:

Python 2.x:

import sys

——————————————

print ‘We are using Python version’, sys.version[:3]

try:

    Some_invalid_code

except NameError, err:

    print err, ‘Error Caused’   # This statement will not work in Python 3.x

——————————————

Output:

——————————————

We are using Python version 2.7

name ‘Some_invalid_code’ is not defined Error Caused

——————————————

Python 3.x:

import sys

 ——————————————

print(‘We are using Python version’, sys.version[:3])

try:

    Some_invalid_code

except NameError as err: # ‘as’ is important here in Python 3.x

    print (err, ‘Error Caused’)

——————————————

Output:

——————————————

We are using Python version 3.8

name ‘Some_inva

lid_code’ is not defined Error Caused

——————————————

Example: Xrange

In Python 3, the “range()” method is used with the behavior and features of xrange() instead of the “xrange()” function from Python 2. Range() is a quicker function than xrange() in terms of speed. Let’s look at the following example:

Python 2.x:

import sys

——————————————

print ‘ Now, we use Python version ‘, sys.version[:3]

for x in xrange(1, 5):  #slow but memory optimal

    print x,

print   #prints next line

for x in range(1, 5):   #faster but takes up memory

    print x, 

——————————————

Output:

——————————————

Now, we use Python version 2.7

1 2 3 4

1 2 3 4

——————————————

Python 3.x:

import sys

——————————————

print(‘We are using Python version’, sys.version[:3])

for x in range(1, 5): #if you replace range with xrange here it will throw an error

   print(x,end=” “)

——————————————

Output:

——————————————

We are using Python version 3.8

1 2 3 4 

——————————————

Example: Raising Exception

Python 3 changes the syntax for raising exceptions. Look at the Python 3 and Python 2 syntax for raising exceptions below.

Python 3.x syntax:

——————————————

raise IOError(“error message”)

——————————————

With Python 3.x, the above syntax will be functional. Check out the Python 2.x syntax in the section below.

Python 2.x syntax:

——————————————

raise IOError, “error message”

——————————————

Because the syntax is not closed between parentheses, it will not function with Python 3. Instead, the system will give an exception.

What Python Version Can Be Used?

Today’s Python 3 version is the clear winner when comparing Python 2 with Python 3 differences. Python 2 won’t be accessible beyond 2020, for this reason. The evident future trajectory is towards widespread Python 3 usage.

It is usually advised for a new developer to choose Python version 3 after taking into account Python 2’s waning support and the benefits of upgrading to Python 3’s new features. The only convincing reason to utilize this version, though, would be if a job required Python 2 skills.

Conclusion

To better enable you to understand the distinctions between the two languages, we have included every significant component of each on this page. This will enable you to  understand the difference between Python 2 and Python 3 and choose which one to learn. A better option could be Python 3. Learn during your convenient learning hours in our Python Training Institute in Chennai.