判断一个数是否是4的n次方

 

def is_Power_of_four(n):  
    while n and not (n & 0b11):  
        n >>= 2  
    return (n == 1)  
  
print(is_Power_of_four(4))
print(is_Power_of_four(12))  
print(is_Power_of_four(16))  
print(is_Power_of_four(255))