📋 Lists & Tuples, lesson 5 of 6
Lists of lists
Model grids, boards and tables with nested lists.
9 min
1 exercise
2 quizzes
0/3 solved
Getting Python ready… examples can run in a moment.
A list can hold other lists. That's perfect for
grids and tables: each inner list is a row. Use
two indexes, row first: grid[row][col].
Example
Tic-tac-toe board
Who wins? Check board[0][0], board[1][1] and board[2][2].
Example
Grade book
Add a row for yourself. row[1:] slices off the name, leaving just the marks.
Quiz
What does this print?
7
5
8
3
Example
The shared-row trap
In bad, changing one row changed all three.
Quiz
What does this print?
7
0
Error
None
Exercise
Sales table
Each row of sales is a day; each column is a
product.
- Append each day's total to
day_totals. - Add each number to its product's slot in
product_totals(column 0, 1 or 2).