Exercise 3: Count a Value

Count how many times a specific value appears in a 2D grid.

grid = [
    [".", "X", "."],
    ["X", ".", "X"],
    [".", ".", "X"]
]

Expected output:

Number of X's: 4

Starter Code

grid = [
    [".", "X", "."],
    ["X", ".", "X"],
    [".", ".", "X"]
]

count = ___

for row in grid:
    for cell in row:
        if ___:
            count += ___

print(f"Number of X's: {count}")

Hints

Hint 1 — Initialize the counter

Start with count = 0 before the loops.

Hint 2 — What to check?

Check if each cell equals "X": if cell == "X":

Hint 3 — Increment

Add 1 each time you find an "X": count += 1

Bonus Challenge

Make it work for any value! Ask the user what to search for:

target = input("What to search for? ")
# Count how many times target appears

Solution

Show Solution

grid = [
    [".", "X", "."],
    ["X", ".", "X"],
    [".", ".", "X"]
]

count = 0
for row in grid:
    for cell in row:
        if cell == "X":
            count += 1

print(f"Number of X's: {count}")

Show Bonus Solution

grid = [
    [".", "X", "."],
    ["X", ".", "X"],
    [".", ".", "X"]
]

target = input("What to search for? ")
count = 0

for row in grid:
    for cell in row:
        if cell == target:
            count += 1

print(f"Number of '{target}': {count}")

Count a Value

Exercise 3: Count a Value

Starter Code

Hints

Bonus Challenge

Solution

Try it yourself

Code: Count a Value