Exercise 2: Find the Largest

Find the largest number in a 2D grid.

grid = [
    [3, 7, 2],
    [9, 1, 5],
    [4, 8, 6]
]

Expected output:

The largest number is 9

Starter Code

grid = [
    [3, 7, 2],
    [9, 1, 5],
    [4, 8, 6]
]

largest = ___

for row in grid:
    for num in row:
        if ___:
            largest = ___

print(f"The largest number is {largest}")

Hints

Hint 1 — Starting value

Start with the first element: largest = grid[0][0]. This way you're comparing against an actual value from the grid.

Hint 2 — When to update?

Update largest whenever you find a number bigger than the current largest: if num > largest:

Hint 3 — Full logic

largest = grid[0][0]
for row in grid:
    for num in row:
        if num > largest:
            largest = num

Bonus Challenge

Also print where the largest number is (its row and column):

The largest number is 9 at row 1, col 0

Bonus Hint

You'll need to use range(len(...)) so you know the row and column indices. Save them when you find a new largest.

Solution

Show Solution

grid = [
    [3, 7, 2],
    [9, 1, 5],
    [4, 8, 6]
]

largest = grid[0][0]
for row in grid:
    for num in row:
        if num > largest:
            largest = num

print(f"The largest number is {largest}")

Show Bonus Solution

grid = [
    [3, 7, 2],
    [9, 1, 5],
    [4, 8, 6]
]

largest = grid[0][0]
largest_r = 0
largest_c = 0

for r in range(len(grid)):
    for c in range(len(grid[r])):
        if grid[r][c] > largest:
            largest = grid[r][c]
            largest_r = r
            largest_c = c

print(f"The largest number is {largest} at row {largest_r}, col {largest_c}")

Find the Largest

Exercise 2: Find the Largest

Starter Code

Hints

Bonus Challenge

Solution

Try it yourself

Code: Find the Largest