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Python program to reverse a given string (5 different ways)
Reversing a string in Python: Here, we are going to learn how to reverse a given string using different ways in Python?
Submitted by Ankit Rai, on July 28, 2019
Input a string from the user and print its reverse.
Example:
Input:
"Ankit"
Output:
"tiknA"
Here, we are implementing the program to reverse a given string using 5 different ways.
1) Using the concept of string Slicing: Take string input from the user then use string slicing concept.
if __name__ == "__main__" :
string = input('Enter a string : ')
# reverse a string using string slicing concept
rev_string = string[::-1]
print("reverse string :",rev_string)
Output
Enter a string : Ankit
reverse string : tiknA
2) Using string concatenation concept: Take string input from the user, simply iterate the string from the last character till the first character and concatenated with previous resultant string.
if __name__ == "__main__" :
string = input('Enter a string : ')
length = len(string)
rev_string = ''
# iteration from the last character till
# first character and cocatenating them
for index in range(length-1,-1,-1) :
rev_string += string[index]
print("reverse string :",rev_string)
Output
Enter a string : Ankit
reverse string : tiknA
3) Make a user-defined function for reversing the string: In this function, we simply iterate the string from the last character till the first character and concatenated with previous resultant string. In last we return the final reverse string.
# define a function for reversing the string
def reverseString(string) :
length = len(string)
rev_string = ''
# iteration from the last character till
# first character and cocatenating them
for index in range(length-1,-1,-1) :
rev_string += string[index]
return rev_string
# Main() method
if __name__ == "__main__" :
string = input('Enter a string : ')
print("reverse string :",reverseString(string))
Output
Enter a string : Ankit
reverse string : tiknA
4) Make a user-defined function for reversing the string: In this function, we simply iterate the string from the last character till the first character and concatenated with previous resultant string. In last we return the final reverse string.
if __name__ == "__main__" :
string = input('Enter a string : ')
# covert string into list of characters
list_char = list(string)
# reverse the list
list_char.reverse()
# join function return string after concatenating the
# elements from the list in given order with empty string
rslt = "".join(list_char)
print("reverse string :",rslt)
Output
Enter a string : Ankit
reverse string : tiknA
5) Using reversed() and join() function: Take string input from user then pass that string in reversed() function . reversed() function returns reversed object which is converted into list using list() function then we are using join() function on this list which gives reversed string.
if __name__ == "__main__" :
string = input('Enter a string : ')
# covert string into list of characters
list_rev = list(reversed(string))
# join function return string after concatenating the
# elements from the list in given order with empty string
rslt = "".join(list_rev)
print("reverse string :",rslt)
Output
Enter a string : Ankit
reverse string : tiknA
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