Python 数字计数器 function 无法正常工作

Question

When I try to make a function that counts the digits in a number, it doesn't work properly, it doesn't show the number of digits,but some random numbers

def count(number):
counter=0
while number>0:
    number/=10
    counter+=1
return counter

can you please tell me what I'm doing wrong?

Answer 1

If we explore what your function is doing, it is just continuously dividing an input number by 10. In math, if you keep dividing a real number not equal to zero (I don't want to get into imaginary numbers) by another larger real number not equal to zero, the result will never equal zero - you will have an infinite list of numbers decreasing in size, getting infinitesimally small.

For example if our number is 10, your function function will set number to:

10
1
.1
.01
.001
.0001
.00001
...

In programming (specifically python), this will continue until the float value is too small for python to differentiate from 0.0, and will return a "random" number.

Another way to accomplish what you are trying to do would be to convert the number to a string and get the length of the string.

def count(number):
    counter = str(number)
return len(counter)

You can also use "floor division", which rounds the result of your division down to the nearest whole integer, if you want to keep your function in a purely mathematical domain.

def count(number):
    counter=0
    while number>0:
        number //= 10
        counter += 1
    return counter