Find position of set bit Python

PROGRAM TO FIND POSITION OF THE ONLY SET BIT

def isPowerOfTwo(n):

    return (True if(n > 0 and 

                   ((n & (n - 1)) > 0)) 

                 else False); 

      

# Returns position of the

# only set bit in 'n'

def findPosition(n):

    if (isPowerOfTwo(n) == True):

        return -1;

  

    i = 1;

    pos = 1;

  

    # Iterate through bits of n 

    # till we find a set bit i&n

    # will be non-zero only when

    # 'i' and 'n' have a set bit

    # at same position

    while ((i & n) == 0):

          

        # Unset current bit and 

        # set the next bit in 'i'

        i = i << 1;

  

        # increment position

        pos += 1;

  

    return pos;

  

# Driver Code

n = 16;

pos = findPosition(n);

if (pos == -1):

    print("n =", n, ", Invalid number");

else:

    print("n =", n, ", Position ", pos);

  

n = 12;

pos = findPosition(n);

if (pos == -1):

    print("n =", n, ", Invalid number");

else:

    print("n =", n, ", Position ", pos);

  

n = 128;

pos = findPosition(n);

if (pos == -1):

    print("n =", n, ", Invalid number");

else:

    print("n =", n, ", Position ", pos);




OUTPUT:

n = 16, Position 5
n = 12, Invalid number
n = 128, Position 8

CREDITS: https://www.geeksforgeeks.org/find-position-of-the-only-set-bit/