Leetcode 191. Number of 1 Bits

"""
Using bit operator AND(&) to compare the number with 1,
if the last bit of the number is 1 which means we found a 1 bit, then update the count by 1;
if the last bit of the number is 0, no need to update the count;
right shif the number as current last bit has been processed.
"""
class Solution:
    def hammingWeight(self, n):
        ans = 0
        while (n):
            ans += n & 1
            n >>= 1
        return ans