如何获取num_digit函数以提供正确的输出，以及如何使其返回python中的任何整数值？

Question

1. How do I get my num_digit function to return 1 instead of 0 whenever I put in 0 as the parameter in the function?

2. How do I get the function to return any integer such as negative numbers?

    def num_digits(n): count = 0 while n: count = count + 1 n = abs(n) / 10 return count 

I was working on question number 2 first. Even if I put the abs(n) in the line of code where while is, I still get an infinite loop which I still do not really understand why. I figured if I can get my n value to always be positive and input in say -24, it would convert it to 24 and still count the number of values.

On question 1, I do not know where to start, ive tried:

def num_digits(n):
    count = 0
    while n:
        if n == 0:
            count = count + 1
            n = n / 10
    return count

I forgot to add I have limited tools to use since I am still learning python. I have gotten up to iterations and am studying the while loops and counters. I have not gotten to break yet although I have an idea of what it does.

Answer 1

When in doubt, brute force is always available:

def num_digits(n):
    if n == 0:
        return 1
    if n < 0:
        return num_digits(abs(n))

    count = 0
    while n:
        count = count + 1
        n = n / 10
    return count

Process the exceptional cases first, and then you only have to deal with the regular ones.

If you want to avoid the conditionals, I suggest taking abs(n) only once, at the beginning, and using an infinite loop + break for the 0 case:

def num_digits(n):
    n = abs(n)
    count = 0
    while True:
        count = count + 1
        n = n / 10
        if n == 0:
            break
    return count

For a more practical solution, you can either count the number of digits in the string (something like len(str(n)) for positive integers) or taking log base 10, which is a mathematical way of counting digits.

Answer 2

  def num_digits(n):
    if n == 0:
        return 0
    return math.floor(math.log10(math.abs(n)))