"""Electrical impedance is the measure of the opposition that a
circuit presents to a current when a voltage is applied.
Impedance extends the concept of resistance to alternating current (AC) circuits.
Source: https://en.wikipedia.org/wiki/Electrical_impedance
"""
from __future__ import annotations
from math import pow, sqrt
def electrical_impedance(
resistance: float, reactance: float, impedance: float
) -> dict[str, float]:
"""
Apply Electrical Impedance formula, on any two given electrical values,
which can be resistance, reactance, and impedance, and then in a Python dict
return name/value pair of the zero value.
>>> electrical_impedance(3,4,0)
{'impedance': 5.0}
>>> electrical_impedance(0,4,5)
{'resistance': 3.0}
>>> electrical_impedance(3,0,5)
{'reactance': 4.0}
>>> electrical_impedance(3,4,5)
Traceback (most recent call last):
...
ValueError: One and only one argument must be 0
"""
if (resistance, reactance, impedance).count(0) != 1:
raise ValueError("One and only one argument must be 0")
if resistance == 0:
return {"resistance": sqrt(pow(impedance, 2) - pow(reactance, 2))}
elif reactance == 0:
return {"reactance": sqrt(pow(impedance, 2) - pow(resistance, 2))}
elif impedance == 0:
return {"impedance": sqrt(pow(resistance, 2) + pow(reactance, 2))}
else:
raise ValueError("Exactly one argument must be 0")
if __name__ == "__main__":
import doctest
doctest.testmod()