Swap all odd and even bits in Python

By Kunal Kamble

Hello friends in this tutorial, we will learn to swap the odd and even bits of a number and write the code for it in Python.

Now let’s explore how we can do it.

For example: The number 43 can be represented as 0 0 1 0 1 0 1 1 in binary. The bits in bold are at even positions which are 0 1 1 1 and the bits at the odd position are 0 0 0 1.

After swapping the odd and even bits we get 0 0 0 1 0 1 1 1 which is 23.

Let’s see how we can swap the odd-even bits

1. Perform bitwise AND operation with hexadecimal 55555555 to extract the odd bits form the number
2. Perform bitwise AND operation with hexadecimal AAAAAAAA to extract the even bits form the number
3. To shift odd bits to even position, perform left shift << by 1 position
4. To shift even bits to odd position, perform right shift >> by 1 position
5. Finally, combine both the bits using bitwise OR operator

Program to Swap Odd and Even bits in Python

Following is the code implementation in Python.

# PROGRAM TO SWAP ODD AND EVEN BITS

print("Enter the number") 
num = int(input())            # take input value of num
odd_bits = num & 0x55555555   # to extract odd bits of num
even_bits = num & 0xAAAAAAAA  # to extract even bits of num
odd_bits = odd_bits << 1      # to shift odd bits to even position     
even_bits = even_bits >> 1    # to shift even bits to odd position

new_num = odd_bits | even_bits  # combining odd and even bits

print("Before swapping bits",num)
print("After swapping bits",new_num)

OUTPUT:

Enter the number
43
Before swapping bits 43
After swapping bits 23