Solution: Number of Digits

Write a function that returns the number of digits for a given integer number.

Rules

1. Input: integer (int) number (+ or -)

2. Solve this challenge without using strings or any external package.

3. The function must return a integer value corresponding to the number of digits of the input number.

Function definition

def get_digits(n):
    n = abs(n)
    length = 1
    i = 10

    while True:
        division = n/i
        if division >= 1:
            length += 1
            i *= 10
        else:
            return length

Testing

Check if your function returns the expected value using the cell below.

import unittest

class UnitTests(unittest.TestCase):
    def test_type(self):
        self.assertTrue(isinstance(get_digits(13124), int), 'The function should return an integer.')
    def test1(self):
        self.assertEqual(get_digits(13124), 5)
    def test2(self):
        self.assertEqual(get_digits(0), 1)
    def test3(self):
        self.assertEqual(get_digits(-12381428), 8)
    def test4(self):
        self.assertEqual(get_digits(12), 2)
    def test5(self):
        self.assertEqual(get_digits(42), 2)
    def test6(self):
        self.assertEqual(get_digits(1000), 4)
    def test7(self):
        self.assertEqual(get_digits(136), 3)
    def test8(self):
        self.assertEqual(get_digits(1000000000), 10)
    def test9(self):
        self.assertEqual(get_digits(2147483647), 10)
unittest.main(argv=[''], verbosity=2,exit=False)  

test1 (__main__.UnitTests) ... 

ok
test2 (__main__.UnitTests) ... 

ok
test3 (__main__.UnitTests) ... 

ok
test4 (__main__.UnitTests) ... 

ok
test5 (__main__.UnitTests) ... 

ok
test6 (__main__.UnitTests) ... 

ok
test7 (__main__.UnitTests) ... 

ok
test8 (__main__.UnitTests) ... 

ok
test9 (__main__.UnitTests) ... 

ok
test_type (__main__.UnitTests) ... 

ok

----------------------------------------------------------------------
Ran 10 tests in 0.005s

OK

<unittest.main.TestProgram at 0x7f2af0a5bfd0>