We will develop a program to reverse a string in python using function. We can also take the help of a function to reverse a string in python using different methods. A function is a block of code that performs a specific task.
The len() function returns the string of items in an object. When the object is a string, the len() function returns the string of characters in the string. The range() method returns an immutable sequence of strings between the given start integer to the stop integer.
Example of reverse string:-
String: Know Program
Reverse String: margorP wonK
Function to Reverse a String in Python
In this program, we use the for loop to reverse a string. The for loop iterates every element of the given string, joining each character in the beginning so as to obtain the reversed string.
# Python program to reverse a string using function
def findReverse(string): #user-defined function
# find reverse of string
reverse = ''
for i in range(len(string), 0, -1):
reverse += string[i-1]
return reverse
# take inputs
string = 'Know Program'
# calling function and display result
reverse = findReverse(string)
print('The reverse string is', reverse)
Output:-
The reverse string is margorP wonK
In the previous program, inputs are hardcoded in the program but in this program, input will be provided by the user.
# Python program to reverse a string using function
def findReverse(string): #user-defined function
# find reverse of string
reverse = ''
for i in range(len(string), 0, -1):
reverse += string[i-1]
return reverse
# take inputs
string = input('Enter the string: ')
# calling function and display result
reverse = findReverse(string)
print('The reverse string is', reverse)
Output for the input values test-case-1:-
Enter the string: Python
The reverse string is nohtyP
Output for the input values test-case-2:-
Enter the string: reverse
The reverse string is esrever
Reverse a String in Python using Function
We are using the while loop to reverse a string. We initialized a while loop with a value of the string.
# Python program to reverse a string using function
def findReverse(string): #user-defined function
#find reverse of string
i = string
reverse = ''
while(len(i) > 0):
if(len(i) > 0):
a = i[-1]
i = i[:-1]
reverse += a
return reverse
# take inputs
string = input('Enter the string: ')
# calling function and display result
reverse = findReverse(string)
print('The reverse string is', reverse)
Output:-
Enter the string: function
The reverse string is noitcnuf
Reverse a String in Python using Recursion
We can also use the recursion technique to reverse a string in Python. A technique of defining the method/function that contains a call to itself is called recursion. The recursive function/method allows us to divide the complex problem into identical single simple cases that can be handled easily. This is also a well-known computer programming technique: divide and conquer.
# Python program to reverse a string using recursion
def findReverse(string): #user-defined function
# find reverse of string
if len(string) == 0:
return string
else:
return findReverse(string[1:]) + string[0]
# take inputs
string = input('Enter the string: ')
# calling function and display result
reverse = findReverse(string)
print('The reverse string is', reverse)
Output:-
Enter the string: recursion
The reverse string is noisrucer
Reverse a String in Python using Slicing
We read a string and reverse a string using slice operations. Syntax of slicing operation:- string[::-1]
# Python program to reverse a string using slicing
def findReverse(string): #user-defined function
# find reverse of string
reverse = string[::-1]
return reverse
# take inputs
string = input('Enter the string: ')
# calling function and display result
reverse = findReverse(string)
print('The reverse string is', reverse)
Output:-
Enter the string: slice
The reverse string is ecils
