Reverse String in Python – Best Approach Given

There are many ways to reverse string in Python. If you are familiar with c , c++ and java and don’t want to use any reverse function then someone could write the logic like:

1. Using the swapping last char with first and do that until the middle character. Remember we used to do this kind of exercise in C, 101?

2. Second would be like to take a new string and add 1 by 1 character from the opposite order of the String. This may take up too much space if you have Essay to reverse.

Note: String is immutable in Python similar to in Java. So it will not change the string if you try to modify, it will create the new String.

Firstly I have not seen a use case where I need to reverse a string unless you are trying to work on Cryptography.

This is enough talking.

Let’s do the reverse string with Python.

Reverse String in Python – Best Approach

This is the best and effective way to reverse a string.

string_sample = "Hello World"

reversed_string  = string_sample[::-1]


This is the very astonished result by writing [::-1] it reverse the String and this is the fastest way to reverse a string.

This is called extended slice syntax. It works by writing [begin:end:step] – (minus sign) by leaving begin and end off and by writing a step of -1 , this will reverse a string.

Here are some other ways to reverse a string in python.

Reverse a String using the recursive function.

def reverse(string):
    if len(string) <= 1:
        return string

    return reverse(string[1:]) + string[0]

string_sample = "Hello World"



Reverse a string by using another string variable and adding character one by one in the opposite of the given string.

def reverse(string):
    new_string = ''
    index = len(string)
    while index:
        index -= 1                    
        new_string += string[index] 
    return new_string

string_sample = "Hello World"

This approach may hurt the performance of the application based on the string length.

Strings concatenation and Formatting in Python

Strings concatenation and Formatting in Python is the process for joining small string to make the bigger. For example, you can create a full name by joining two string like Firstname and Lastname. Formatting will help to display variable in or end of the string.

Strings Concatenation in Python

Python provides the easy way to concatenate Strings by using + (plus)  and * (star) Sign. There are other methods such as append(), join() and format().

Using + 

+ will adds values on either side of the operator

Here is an example :

Using *

*  Creates new strings, concatenating multiple copies of the same string.

Here is an example :

String Formatting in Python

You might have the experience to use C language to print String and Integer using %s and %d. Python has similar string formatting to create new, formatted strings. The % operator is used to format variables.

Here are the examples:

String formatting using two and more than values using the tuple. A tuple is a sequence of immutable Python objects. Tuples use parentheses.

Python is supporting other function like append and join to manipulate String data.

Python Interpreter : The Best Language Interpreter

Python language is written by Guido van Rossum in late 1980 is one of the Best interpreted languages. Python is used as the first programming choice of both Google, Ubuntu, RedHat. Python Interpreter is the best interpreter.

The Python interpreter

The Python interpreter is a program that reads Python program statements and executes them immediately. To use interpreter it requires opening the command prompt or terminal windows in your development environment and write command python, and it will show this result and start interpreter. I am using Window 10’s Ubuntu shell.

Python interpreter executes program statements immediately. To Experiment python statements , Python command will start interactive mode and it will be very useful to try out things.

Here are some Examples of one-line commands:

In above examples, one will print Hello World, other will do multiplication and the third one calculates Decimal to Binary using bin().

The >>> prompt is used to enter one-line commands or code blocks that define classes or functions . In above example, only one-liner commands are given. In next example please find multi-line code blocks.

Here are some Examples of multi-line code block:

In above example, it will compare two strings.

help() function is another awesome way to get help on python keywords, functions, etc.

Here is the example of checking syntax and guide of bin command. Press q to return to python interactive interpreter.

I love the way Python Interactive Interpreter works. How about you?


10 Python Tips and Tricks for Beginner and 9th is interesting

Today Python is one of the most popular languages for coding in Unix/Linux world. You can find it everywhere from Web development to Server Component development, XML parsing to configuration management. Here I will be mentioning 10 Python tips and tricks for developers.

Python is pre-installed in many Operating Systems which released in last two year. Ubuntu, Redhat, Mac OS, Free BSD , Solaris, etc.

To check which version of python is installed go to shell and type:

$ python

This command will give you the version information of Python and start Python’s interactive interpreter.

Here are the few famous applications which are built using Python such as :

  • Youtube
  • OpenStak
  • Dropbox
  • Instagram

Here are 10 Python tips and tricks for Beginners and Experts.

1. Use Python Development Environment

By using Development Environment or IDE it will increase your productivity and easy to resolve error and warning. It will also help to debug the code, easy to navigate , integrate source control such as SVN, Git.

These are the recommended IDEs for Python Development.

  • PyDev – It’s free and Open Source Eclipse-based IDE .
  • IDLE : The Python built-in IDE, with auto-completion, helps to Format , Run and Debug python code.
  • Other commercial versions are PyCharm, WingIDE.

2. Calculate days between Today and Date.

import datetime

today =

someday =, 1, 1)

diff = someday - today

print (str(diff.days) +" days")

datetime module is used to find the days between two dates. this example will find the days between today and 1 Jan 2017.

3.Command line arguments while running Python Scripts

#file name is
import sys

print 'No of arguments passed:', len(sys.argv)
print 'List of arguments :', str(sys.argv)

run this script:

$ python 10 20 30

No of arguments passed: 3
List of argumenrs : ['', '10', '20', '30']

sys module will have the information about arguments passed by accessing sys.argv variable. sys.argv is a list of strings representing the arguments on the command-line.

4. String Searching made easy

First Method will check if a string contains another string by using the in syntax. in takes two arguments, first on the left and second on the right, and returns True if the left argument is contained within the right argument.

s = "This is a String finding program"

# Method 1
if 'String' in s:
    print('String is found in this program')
# Method 2    
if s.find('String') != -1:
    print('String is at ' , s.index('String'))

Second Method offers a Library method called find(). This method is used with String Variable and it returns the position of the index of desired string. If the string is not found then -1 is returned.

5. Generating Random Numbers

Python is having the random library for generating random numbers. By default random library uses system time to generate random numbers.

import random
print('Random number:->' , random.randrange(10));

print('Random Range Between 10 to 20:->' , random.randrange(10,20));

print('Random with Floating values:->' , random.uniform(0,10));

Output :
Random number:-> 9
Random Range Between 10 to 20:-> 13
Random with Floating values:-> 5.012076169955613

random.randrange(10) sets the limit from 0 to 10 and return numbers between 0 to 10.

random.randrange(10,20) gives random values between 10 to 20.

random.uniform gives the result with floating value.

6. Opening WebBrowser from Python Script

import webbrowser'')

webbrowser module provides the easy way to open system’s default browser with URL mention in open method.

7. Calculate Program Execution time

import time
start_time = time.time()

add = 0
for i in range(1, 10000):
    add =add + i

print("\n--- %s seconds ---" % (time.time() - start_time))

Many applications require a very precise time measurement. For this purpose, Python provides methods in time module. These methods will help you to measure execution time taken by the block of code.

In Linux and Unix, this command can let us know the execution of the python program.

$ time python

8. Converting the List to a String for Print

#declaring List
mylist = ['one', 'two', 'three']

print (', '.join(mylist))
print ('\n'.join(mylist))

To combine any list of strings into a single string, use the join method of a string object. First print statement will join string with ” , ” and second will add new line.

one, two, three

9. Strings Concatenating using ” + ” and more.

Python uses + and * from manipulating String.

Using +

$ python
>>> print "Jhon" + "Doe"

Using *

>>> print "Jhon" * 3

10. Sorting Array of String

mylist = ['one', 'two', 'three', 'four', 'five']


for x in mylist:
    print (x);


Let me know your views and best Python tips in comment below.

Validate JSON using Python

Python has built-in JSON module to work with JSON data. Python is getting popular and becoming the first choice of startup development. JSON is used widely because it easy to understand, compact and built in support in JavaScript.

Validating JSON Using Python.

json.loads() method is used to validate JSON data.

Here is the function which will validate JSON data.

#JSON Validator function
import json

def json_validator(data):
        return True
    except ValueError as error:
        print("invalid json: %s" % error)
        return False


json.loads() loads the JSON data to parse, it will return true or it will fail and raised the exception. This function will work as EAFP (Easier to ask for forgiveness than permission). EAFP is python’s ideology to handle this kind of situation.

Here is the Example of Validating JSON data using Python.

#Validating JSON using Phython Code
import json

def json_validator(data):
        return True
    except ValueError as error:
        print("invalid json: %s" % error)
        return False

#Valid JSON Data
""" {
  "actors": {
    "actor": [
        "id": "1",
        "firstName": "Tom",
        "lastName": "Cruise"

#Invalid JSON Data
    "actor": [
        "id": "1",
        "firstName": "Tom",
        "lastName": "Cruise"

print(json_validator('{"actors":{"actor":[{"id":"1","firstName":"Tom","lastName":"Cruise"}]}}' ))#prints True

print (json_validator('{{"actor":[{"id":"1","firstName":"Tom","lastName":"Cruise"}]}}')) #prints Error message and False


These ready-made tools can be used to validate JSON data online JSON Validator on CodeBeautify. and Json Validator.