如何让它准确检测数字中有多少位？

Question

I am trying to get my code to show each digit individually on its own line, and it does do that. However, I am getting an error at the end of it, so I want to detect exactly how many digits are in the number. I am having trouble finding a solution for this that isn't len(), because for this specific program I am not supposed to use it.

Here's my code:

number = int(input("Enter a positive integer: "))
number = str(number)
digits = 0
while True:
    print(number[digits])
    digits += 1

Answer 1

You can create a counter and with a while loop should look like:

num = int(input("enter num"
result = 0

while num > 10:
  num = num // 10
  result += 1

result += 1


print(result)

Answer 2

It throws an error because you are running an infinite while loop. Use for instead.

number = int(input("Enter a positive integer: "))
number = str(number)
digits = 0
for i in number:
    print(i)
    digits+=1

Answer 3

You can also use the log10 (logarithm with base 10) function:

import math
number = int(input("Enter a positive integer: "))
print(1 + int(math.log10(number)))

Answer 4

You can solve your problem just by printing elements of string concatenated with new-line delimiter without attempts to find how many elements in string:

number = input("Enter a positive integer: ")
print('\n'.join(number))

Answer 5

Just enumerate number.

number = int(input("Enter a positive integer: "))
number = str(number)
for n, number in enumerate(number, start=1):
    print(number)
print(f'Total length: {n}')

# Example:
Enter a positive integer: 514
5
1
4
Total length: 3

The problem with your existing code is the while True: line with no breaks. One method to get around that would be:

digits = 0
while True:
    try:
        print(number[digits])
        digits += 1
    except IndexError:
        break

Although it is preferable to avoid this altogether by using a simpler solution.

Answer 6

The reason you're getting the error is because when the digits acquires the value of the length of the number say l , then number[l] doesn't exist (The indices start from 0)

number = input("Enter a positive integer: ")) 

# type(number) is <class 'str'> you don't have to convert to int and reconvert to string

# since <class 'str'> implements iterable you could go like this ..

digits = 0 

for digit in number:

     print(digit)  # digit is still a str here

     digits += 1