Code Fights - firstDigit

README.md

Find the leftmost digit that occurs in a given string.

Example

• For inputString = "var_1__Int", the output should be
  firstDigit(inputString) = '1';
• For inputString = "q2q-q", the output should be
  firstDigit(inputString) = '2';
• For inputString = "0ss", the output should be
  firstDigit(inputString) = '0'.

Input/Output

• [time limit] 4000ms (py3)

• [input] string inputString

  A string containing at least one digit.

  Guaranteed constraints:

   3 ≤ inputString.length ≤ 10.
  

• [output] char

first_digit.py

import re


def first_digit(input_string: str):
    return re.search(r'\d', input_string).group()
  

test_first_digit.py

import unittest
from first_digit import first_digit


class TestFirstDigit(unittest.TestCase):
    def test_1(self):
        input_string = 'var_1__Int'
        solution = '1'
        result = first_digit(input_string)
        self.assertEqual(result, solution)

    def test_2(self):
        input_string = 'q2q-q'
        solution = '2'
        result = first_digit(input_string)
        self.assertEqual(result, solution)

    def test_3(self):
        input_string = '0ss'
        solution = '0'
        result = first_digit(input_string)
        self.assertEqual(result, solution)


if __name__ == '__main__':
    unittest.main()