for Loops and range()

Loops in Python

Python's for loop iterates over a sequence. Use range() to generate number sequences:

for i in range(5):
    print(i)
# Output: 0, 1, 2, 3, 4

for i in range(1, 6):
    print(i)
# Output: 1, 2, 3, 4, 5

for i in range(0, 10, 2):
    print(i)
# Output: 0, 2, 4, 6, 8  (step size 2)

Iterating over a list

colors = ["red", "green", "blue"]
for color in colors:
    print(color)

Accumulating values

total = 0
for i in range(1, 6):
    total += i   # total = total + i
print(total)  # 15

Your task

Write a function factorial(n) that computes n!
n! = 1 × 2 × 3 × ... × n

Example: 5! = 1 × 2 × 3 × 4 × 5 = 120