A map of the bus, not the bus
A bus map shows the stops and the routes. It does not show the seats, the paint or the bus number plate.
The map leaves out almost everything, and that is why you can read it. A data analyst does the same with a long sales sheet. They keep what helps and drop what does not.
By the end of this lesson
Note
I can use abstraction (keeping what matters) to list what a solution needs, what changes and what stays the same.
Key words
| Word | What it means |
|---|---|
| Abstraction | Keeping the details that matter and hiding the rest |
| Filter | Remove what you do not need |
| Input | Information that goes in |
| Output | Information that comes out |
| Variable | A value that can change |
| Constant | A value that stays the same |
| Internal working | How a part does its job inside |
The cells students fill in are left blank in this preview.
Starter
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Starter
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
Abstraction removes the noise
The purpose of abstraction is to make a problem simple enough to think about. A sales sheet might hold 40 columns. Only a few help you answer the question.
Abstraction has three tasks. Identify the information you need. Filter out what you do not need. Hide the internal workings of parts you only need to use.
Three tasks, one question
| Task | Example: "Which day sells most?" |
|---|---|
| Identify information that is needed | The date and the sale amount |
| Filter out unnecessary details | The till colour, the name of the cashier |
| Hide the internal workings | You use the sum tool without knowing how it adds |
The cells students fill in are left blank in this preview.
Check
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Check
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.