1 - Start: What We're Building ~4 mins
You can already run Python on the micro:bit and show values on the LED display.
Today you will store a collection of values in a list, change that list, and loop over it to build LED light patterns.
Before you run anything, think: if a list holds five numbers and you ask for the item at index 0, which number do you expect?
Keep this short. Devices on the micro:bit Python editor, students logged in. Optional predict: before anyone runs code, ask what item they expect at index 0 in a list of five numbers. Do not let the start run long; time belongs on the build. Pair students when they move to the editor.
2 - Introduction ~2 mins
In this lesson, you'll learn the basics of working with arrays in MicroPython. You'll create a simple list, retrieve elements from the list, change elements, add new elements, and remove elements from the list. By the end of this lesson, you'll have a solid understanding of how to work with arrays in MicroPython.
To get started, open the micro:bit Python editor at https://python.microbit.org and create a new project.
Frame this as the lesson map only. Confirm every student has a new project open in the micro:bit Python editor. Do not rush into typing; check that boards or the simulator respond. Differentiation: sit nearer anyone still opening the editor.
3 - What Is an Array? ~2 mins
An array is a collection of items, like numbers or strings, stored in a single variable. In MicroPython, arrays are often called lists. They are useful when you want to store and manipulate multiple values using a single variable.
In this lesson, we'll use the terms 'array' and 'list' interchangeably.
Clarify in plain language: a list is one variable that holds many values in order. Note that this course says list (array may appear in the step text). Key question: when would one named list be more useful than five separate variables? Keep it brief and move on.
4 - Create a List ~2 mins
Lists can store different types of data, such as integers, strings, or even other lists. For example:
- Integer List:
[1, 2, 3, 4, 5] - String List:
['apple', 'banana', 'cherry'] - Mixed List:
[1, 'apple', 3.14]
Now, let's create a list called 'numbers' with five elements. The elements are the integers from 1 to 5. Add the following code to your editor:
from microbit import *
numbers = [1, 2, 3, 4, 5]
numbers with five elements. The elements are the integers from 1 to 5.Model creating the numbers list on the board. Stress the square brackets and commas. Common bug: missing comma or bracket so the editor errors. Have pairs run once they match the step. Support: let them copy carefully from your board version first.
5 - Retrieve List Elements ~2 mins
Now, let's retrieve elements from the list using their index. Add the following new code:
from microbit import *
numbers = [1, 2, 3, 4, 5]
first_number = numbers[0]
second_number = numbers[1]
display.show(first_number)
sleep(1000)
display.show(second_number)This code retrieves the first and second elements of the list (at index 0 and 1) and displays their values.
numbers[index_value] to retrieve different items from the list, and run your code again. e.g. numbers[3] will retrieve the forth item in the list.
PRIMM investigate beat. Ask before they run: which value is at index 0, and which at index 1? Watch for the off-by-one misconception (thinking the first item is [1]). Encourage them to try another index and predict before running. Board cue: write the list with indexes labelled underneath.
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