Workshop › Sudoku › Step 8 of 28

The same digit everywhere

What we are doing

When the selected cell holds a digit, every cell with the same digit lights up in blue: you see at once where that digit already is.

```js
const d = selected && grid[selected.r][selected.c]

    if (d && grid[r][c] === d) fill = '#bfdbfe'
```

What it means

• d is the digit in the selected cell (0 if it is empty), worked out once before the loops.
• d && ... skips the rule when the cell is empty (0 counts as false).

Your turn

1. In draw, write the d line above the cell loops.
2. Under the grey rule, write the same-digit rule.

Skills: Game states

← Light up row, column and box Click to select →

All steps

1. Nine by nine
2. Lines and boxes
3. A puzzle from a string
4. The puzzle's own digits
5. Keep drawing
6. The selected cell
7. Light up row, column and box
8. The same digit everywhere
9. Click to select
10. Move with the arrows
11. Write digits
12. The three rules in one loop
13. Show mistakes
14. Solved!
15. A clock
16. The solved message
17. Play again
18. The easiest cell
19. The solver
20. Random order
21. Invent a puzzle
22. A new puzzle every game
23. Hints
24. Best time
25. N for a new puzzle
26. A number pad
27. Tap the pad
28. Build it yourself: undo