🐍 Lesson 7: Loops

Use a for loop with range() to print the numbers 1 through 5, each on its own line.

for i in range(1, 6):
    print(i)

Print Go Team! (with a trailing space) 3 times on one line. Hint: print("Go Team! ", end="") keeps printing on the same line.

for i in range(3):
    print("Go Team! ", end="")

Print the even numbers from 2 to 10. Two ways to try: use range(2, 11, 2), or loop 1–10 and check % 2 == 0.

for n in range(2, 11, 2):
    print(n)

Use a loop to add up all the numbers from 1 to 10 and print the total (it's 55). Hint: start with total = 0 and add each number inside the loop.

total = 0
for n in range(1, 11):
    total += n
print(total)

Make a countdown using a while loop! Start at 10, count down to 1, then blast off. Add your own emojis and messages.

Print the 7 times table from 7 × 1 to 7 × 10, one line each, in the form 7 x 1 = 7. Use a for loop with range(1, 11).

for i in range(1, 11):
    print(f"7 x {i} = {7 * i}")

Add up every whole number from 1 to 100 with a loop and a total variable, then print the answer. (Legend says a schoolboy named Gauss did this in his head in seconds!)

total = 0
for n in range(1, 101):
    total += n
print(total)

Use a while loop to count down from 5 to 1, one number per line, then print Blast off!. Do not forget to make the number smaller each time, or the loop will never stop!

n = 5
while n > 0:
    print(n)
    n -= 1
print("Blast off!")

A for loop can walk through text one character at a time. Loop over "PYTHON" and print each letter on its own line.

for letter in "PYTHON":
    print(letter)

Loop over range(1, 11). Use continue to skip the number 5 entirely, and break to stop completely once you reach 8. Print the numbers that survive.

for n in range(1, 11):
    if n == 5:
        continue
    if n == 8:
        break
    print(n)

Without using max(), find the largest number in scores = [12, 45, 7, 98, 33] with a loop and print it. Start with biggest = scores[0] and replace it whenever you meet something larger.

scores = [12, 45, 7, 98, 33]
biggest = scores[0]
for s in scores:
    if s > biggest:
        biggest = s
print(biggest)

Print a triangle of stars 5 rows tall: one star on row 1, two on row 2, and so on. Hint: "*" * n repeats the star.

for n in range(1, 6):
    print("*" * n)

Nested loops build grids. Print a 3 × 3 grid of coordinate pairs like (1,1) — three per line, separated by spaces. Hint: an inner loop with end=" ", then an empty print() to end the row.

for row in range(1, 4):
    for col in range(1, 4):
        print(f"({row},{col})", end=" ")
    print()

The most famous interview question ever! For numbers 1 to 20: print Fizz if the number divides by 3, Buzz if it divides by 5, FizzBuzz if it divides by both, otherwise the number itself. Check the both-case first!

for n in range(1, 21):
    if n % 3 == 0 and n % 5 == 0:
        print("FizzBuzz")
    elif n % 3 == 0:
        print("Fizz")
    elif n % 5 == 0:
        print("Buzz")
    else:
        print(n)

Invent your own loop art: a diamond, a chessboard, a staircase, a spiral of emojis. Mix * repetition, nested loops and end="" until it looks great. 🎨