Python Program to Reverse a String (Different Ways)

1. Introduction

Reversing a string or a sequence is a common operation in programming. It can be required in various scenarios such as data processing, cryptography, or simply as an exercise to learn about string manipulation techniques. Python provides multiple methods to reverse strings or lists.

Reversing a string or list means arranging its elements or characters in the opposite order so that the first becomes last and the last becomes first.

2. Program Steps

1. Reverse a string using slicing.

2. Reverse a string using the reversed() function.

3. Reverse a string using a loop.

3. Code Program

# Reverse a string using slicing
def reverse_string_slicing(str_to_reverse):
    return str_to_reverse[::-1]

# Reverse a string using the reversed() function
def reverse_string_reversed(str_to_reverse):
    return ''.join(reversed(str_to_reverse))

# Reverse a string using a loop
def reverse_string_loop(str_to_reverse):
    reversed_str = ''
    for char in str_to_reverse:
        reversed_str = char + reversed_str
    return reversed_str

# Input string
input_str = "Python"

# Reverse the string using different methods
reversed_by_slicing = reverse_string_slicing(input_str)
reversed_by_reversed = reverse_string_reversed(input_str)
reversed_by_loop = reverse_string_loop(input_str)

# Print the output
print(f"Original string: {input_str}")
print(f"Reversed by slicing: {reversed_by_slicing}")
print(f"Reversed by reversed function: {reversed_by_reversed}")
print(f"Reversed by loop: {reversed_by_loop}")

Output:

Original string: Python
Reversed by slicing: nohtyP
Reversed by reversed function: nohtyP
Reversed by loop: nohtyP

Explanation:

1. reverse_string_slicing uses the slicing method with a step of -1 to reverse str_to_reverse.

2. reverse_string_reversed uses the reversed() function which returns an iterator that accesses the given string in the reverse order. The ''.join() method then combines the characters into a new string.

3. reverse_string_loop initializes an empty string reversed_str and prepends each character from str_to_reverse to build the reversed string.

4. input_str is defined as "Python".

5. The three functions are called with input_str, and the results are stored in corresponding variables.

6. Each reversed string is printed alongside the method used for the reversal.