Antwoorden — Hoofdstuk 4: Lussen en iteraties

Opmerking: Code is in het Engels, met korte Nederlandse toelichting erboven of eronder.

Antwoord 1 — Tellen met range

• range(1, 11) geeft 1..10 (stop is exclusief). We bouwen één regel met end=" ".

for i in range(1, 11):
    print(i, end=" ")
print()  # newline

Antwoord 2 — Som 1..n (accumulatie)

n = int(input("n: "))
total = 0
for i in range(1, n + 1):
    total += i
print(total)

Antwoord 3 — While-teller omlaag

n = 5
while n >= 1:
    print(n)
    n -= 1
print("Liftoff!")

Antwoord 4 — Alleen even getallen (continue)

n = 0
while n < 20:
    n += 1
    if n % 2 != 0:
        continue
    print(n)

Antwoord 5 — Eerste veelvoud vinden (for-else)

• Bij break slaan we het else-deel over; zonder break draait else.

for i in range(1, 51):
    if i % 7 == 0 and i % 5 == 0:
        print("Found:", i)
        break
else:
    print("No match")

Antwoord 6 — Genummerde lijst (enumerate)

names = ["Ava", "Bo", "Cid", "Dia"]
for idx, name in enumerate(names, start=1):
    print(f"{idx}. {name}")

Antwoord 7 — Itereren over dict

user = {"name": "Liam", "age": 31, "city": "Rotterdam"}
for key, value in user.items():
    print(f"{key}: {value}")

Antwoord 8 — Tafel van vermenigvuldiging (genest)

for a in range(1, 11):
    for b in range(1, 11):
        print(f"{a*b:>4}", end="")
    print()

Antwoord 9 — Invoer tot leeg (sentinel)

count = 0
while True:
    line = input().strip()
    if line == "":
        break
    count += 1
print(f"Count: {count}")

Antwoord 10 — Filter en transformeer

nums = [3, 8, 1, 7, 2, 10, 5]

# filter evens
evens: list[int] = []
for x in nums:
    if x % 2 == 0:
        evens.append(x)

# transform squares
squares: list[int] = []
for x in nums:
    squares.append(x * x)

print(evens)
print(squares)

Uitdaging (optioneel) — FizzBuzz 1..100

for i in range(1, 101):
    if i % 15 == 0:
        print("FizzBuzz")
    elif i % 3 == 0:
        print("Fizz")
    elif i % 5 == 0:
        print("Buzz")
    else:
        print(i)