Lesson 17 of 30
Lesson 17 ? Nested lists and grids
Title: Make tiny maps with lists inside lists
Description: Use nested lists to build rows, columns, and simple game boards.
Why it matters for kids: Many games use grids: tic-tac-toe, mazes, maps, and puzzles.
1. A row of tiles
row = ["grass", "grass", "water"]
print(row[0])
print(row[2])2. A tiny map
world = [
["grass", "tree", "grass"],
["water", "bridge", "water"],
["grass", "house", "grass"],
]
print(world[1][1])world[1][1] means row 1, column 1.
3. Print each row
world = [
[".", ".", "T"],
["~", "B", "~"],
[".", "H", "."],
]
for row in world:
print(row)4. Pretty grid
world = [
[".", ".", "T"],
["~", "B", "~"],
[".", "H", "."],
]
for row in world:
print(" ".join(row))5. Easy examples
board = [
["X", "O", "X"],
["O", "X", "O"],
["O", "X", "X"],
]
print(board[0][0])seats = [
["A1", "A2"],
["B1", "B2"],
]
print(seats[1][0])pixels = [
["red", "red"],
["blue", "blue"],
]
print(pixels)6. Mini challenge
Click each example to open it.
Example 1
Create one row with three tiles.
Example 2
Print the first tile.
Example 3
Create a 2 by 2 grid.
Example 4
Print row 0 column 0.
Example 5
Create a 3 by 3 map.
Example 6
Put X in one place.
Example 7
Print every row.
Example 8
Join one row with spaces.
Example 9
Make a tiny tic-tac-toe board.
Example 10
Make a tiny classroom seating grid.