Day 10: for Loop and range()

Quick Answer

What You Will Learn

• range(5) produces 0 to 4. The number 5 itself is not included.
• range(2, 11, 2) starts at 2, stops before 11, and steps by 2: 2, 4, 6, 8, 10.
• sum(range(1, 11)) adds 1 to 10 and gives 55.
• enumerate() gives both a number and an item while looping over a list.
• Use for when you know what to loop over or how many times to loop.

Code

for i in range(5):
    print(i, end=" ")
print()
print(list(range(2, 11, 2)))
print(sum(range(1, 11)))
for i, f in enumerate(["mango", "banana"], start=1):
    print(i, f)
for i in range(1, 4):
    print(f"5 x {i} = {5 * i}")

Output

0 1 2 3 4 
[2, 4, 6, 8, 10]
55
1 mango
2 banana
5 x 1 = 5
5 x 2 = 10
5 x 3 = 15

Code Explained, Line by Line

1. range(5) produces 0 to 4. The number 5 itself is not included.
2. range(2, 11, 2) starts at 2, stops before 11, and steps by 2: 2, 4, 6, 8, 10.
3. sum(range(1, 11)) adds 1 to 10 and gives 55.
4. enumerate() gives both a number and an item while looping over a list.
5. Use for when you know what to loop over or how many times to loop.

Real-Life Use

Tables, lists of items and repeated calculations in apps are all for loops.

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