Initialising subclasses with super()

Beginner Python OOP Inheritance

Created by Pavel · 07.03.2026 at 19:57 UTC · 5 completed

Sensors share an identifier and a readings buffer; a temperature sensor adds a unit string. If the child __init__ forgets super().__init__(...), the parent fields never appear and every later method assumes a broken object.

super() is the cooperative spelling: it respects MRO, which matters the moment you mix in another base. Hard-coding Sensor.__init__(self, ...) in one child often breaks when the hierarchy grows.

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Tasks

Question 1

What is the recommended way to call a parent class constructor?

Hint

It respects method resolution order

Parent.init(self, ...)

super().init(...)

self.init(...)

base.init(...)

Question 2

Sensor with __init__(self, sensor_id) setting self.sensor_id and self.readings = [].
TemperatureSensor(Sensor) with __init__(self, sensor_id, unit) calling super().__init__(sensor_id) and self.unit = unit.
t = TemperatureSensor("S42", "°C") then print(t.sensor_id, t.unit).

Expected stdout: S42 °C (space-separated).

Hint

print two attributes separated by a space.

class Sensor:
    def __init__(self, sensor_id):
        # TODO: sensor_id and empty readings list
        pass


class TemperatureSensor(Sensor):
    def __init__(self, sensor_id, unit):
        # TODO: super() then set unit
        pass


# TODO: print sensor_id and unit for S42 / °C

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Card Info

Topic: Python OOP Inheritance
Difficulty: Beginner
Completed: 5 users

Creator

Pavel