How to count the number of bits in the digits in python

Question

I am trying to count the number of bits in the given number using python:

def countBit(self, n: int) -> int:
    l=[int(d) for d in str(n)]
    return(sum(l))

The input given to this function is 00000000000000000000000000001011 and the output expected is 3 but I am getting 2 as the output.

Can you suggest me a way to proceed ?

Answer 1

You're adding the digits in the decimal representation of the number, not the binary representation.

From your expected output, I guess you actually want to only count the 1 bits, not the 0 bits.

Use the bin() function to convert the number to a binary string.

def countBit(n: int) -> int:
    return sum(b == '1' for b in bin(n))