Topics and topic hierarchy in IOT Protocols - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to publish a message to the correct MQTT topic.

IOT Protocols

client.publish('[1]', 'Hello World')

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Ahome-kitchen-temperature

Bhome/kitchen/temperature

Chome.kitchen.temperature

Dhome_kitchen_temperature

Attempts:

3 left

💡 Hint

Common Mistakes

Using underscores or dots instead of slashes in topic names.

The MQTT topic uses slashes / to separate levels in the topic hierarchy.

2fill in blank

medium

Complete the code to subscribe to all temperature topics under 'home'.

IOT Protocols

client.subscribe('[1]')

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Ahome/temperature/#

Bhome/#/temperature

Chome/temperature/+

Dhome/+/temperature

Attempts:

3 left

💡 Hint

Common Mistakes

Using # in the middle of the topic, which is invalid.

The plus sign + is a single-level wildcard in MQTT topics.

3fill in blank

hard

Fix the error in the topic filter to subscribe to all sensors under 'home'.

IOT Protocols

client.subscribe('[1]')

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Ahome/#

Bhome/+/#

Chome/+/+

Dhome/+/sensor/#

Attempts:

3 left

💡 Hint

Common Mistakes

Using # in the middle of the topic filter.

The # wildcard matches all subtopics from the point it is used.

4fill in blank

hard

Fill both blanks to create a topic filter that matches any sensor data in any room under 'home'.

IOT Protocols

client.subscribe('home/[1]/[2]')

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A+

B#

Csensor

Ddata

Attempts:

3 left

💡 Hint

Common Mistakes

Using # too early or in the wrong position.

The first + matches any single room, and # matches all subtopics after that.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps sensor names to their latest values from a topic list.

IOT Protocols

sensor_data = { [1]: [2] for [3] in topics if 'sensor' in [3] }

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Atopic.split('/')[-1]

Bvalue

Ctopic

D{topic: value}

Attempts:

3 left

💡 Hint

Common Mistakes

Using the whole topic string as the key instead of the sensor name.

This comprehension extracts the sensor name from the topic string and maps it to its value.