Challenge 163 - Calculate the Missing Value with Ohm's Law

challenge_163.md

Challenge 163 - Calculate the Missing Value with Ohm's Law

Create a function that calculates the missing value of 3 inputs using Ohm's law. The inputs are v, r or i (aka: voltage, resistance and current).

Ohm's law:

V = R * I

Return the missing value rounded to two decimal places.

Examples

ohms_law(v=12, r=220) ➞ 0.05

ohms_law(v=230, i=2) ➞ 115

ohms_law(r=220, i=0.02) ➞ 4.4

ohms_law(i=10) ➞ "Invalid"

ohms_law(v=500, r=50, i=10) ➞ "Invalid"

Notes

• Missing values will be None
• If there is more than one missing value, or no missing value, return "Invalid"
• Only numbers will be given.

challenge_tests.py

from typing import Optional, Union
import unittest


Number = Union[float, int]
Value = Optional[Number]


def ohms_law(v: Value = None, r: Value = None, i: Value = None) -> Union[Number, str]:
    return 0  # Put your code here!!!


class Test(unittest.TestCase):
    def test_1(self):
        self.assertEqual(ohms_law(v=12, r=220), 0.05)

    def test_2(self):
        self.assertEqual(ohms_law(v=230, i=2), 115)

    def test_3(self):
        self.assertEqual(ohms_law(r=220, i=0.02), 4.4)

    def test_4(self):
        self.assertEqual(ohms_law(i=10), "Invalid")

    def test_5(self):
        self.assertEqual(ohms_law(v=500, r=50, i=10), "Invalid")


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

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