What are some interesting bitwise exercises in Python?

What are some interesting bitwise exercises in Python?

Here are a few exercises you can try:

1. Implement a function to swap two numbers using bitwise XOR.
2. Create a function to check if a number is a power of two using bitwise operations.
3. Write a function to count the number of 1s in the binary representation of a number.

Can you explain how to swap two numbers using bitwise XOR?

Sure! To swap two numbers a and b using XOR:

1. Set a = a ^ b
2. Set b = a ^ b (now b is the original a)
3. Set a = a ^ b (now a is the original b) This works because XORing a number with itself results in 0, and XORing with 0 returns the original number.

What about checking if a number is a power of two?

You can check if a number n is a power of two by using the expression n > 0 and (n & (n - 1)) == 0. This works because powers of two have only one bit set in their binary representation.

Can you give me a code example for counting the number of 1s?

Certainly! Here's a simple function:

def count_ones(n):
    count = 0
    while n:
        count += n & 1
        n >>= 1
    return count

This function counts the number of 1s in the binary representation of n.