One long line of text
A server writes this line: "2026-10-28 14:32 ERROR disk full".
To a person it says when, how bad and what. To a computer it is one long piece of text. To count the errors, you must first pull the pieces out and give each a type.
By the end of this lesson
Note
I can explain how layout, type and conversion work together, and choose well.
Key words
| Word | What it means | Example |
|---|---|---|
| Structured data | Data in a fixed layout of fields. | A table of tickets |
| Unstructured data | Data with no fixed layout. | A log line |
| Data type | The kind of value a field holds. | Integer |
| Integer | A whole number. | 42 |
| String | Text made of characters. | LAPTOP-07 |
| Blob | A large object such as a photo, stored whole. | A screenshot |
| Convert | To change a value from one type to another. | Text "12" to the integer 12 |
| Extract | To pull one piece out of a larger item. | The level from a log line |
| Lossy | A change that throws some detail away. | 21.9 becomes 21 |
The cells students fill in are left blank in this preview.
Starter: what you already know
Have a go
Starter: what you already know
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
Layout, type and conversion are linked
In structured data every field has its own data type. A date field holds dates and an integer field holds whole numbers. That is what makes it easy to sort and total.
Unstructured data is usually held as one string or one blob. It has no fields yet, so the computer cannot sort by part of it.
Changing type changes what you can do
To use unstructured data you extract pieces and convert each to a type. The text "14:32" becomes 872 minutes. Now you can add and compare.
Some changes are lossy. An integer cannot hold 21.9, so converting drops the .9. Some fail: "banana" cannot become an integer.
Check: layout, type and change
Have a go
Check: layout, type and change
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.