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Python: from first line to project · Lesson 06 / 12
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Repeat with a clear path

Adding ten, twenty and fifteen minutes by hand works. A loop repeats the same rule when the list changes.

Learning paths10 min

Let's discover together

  1. 1

    for minutes in durations visits one value at a time, in list order. The indented block repeats for each value.

  2. 2

    Start total = 0 before the loop. total = total + minutes accumulates: first 10, then 30, then 45. Resetting total inside the loop would lose earlier values.

  3. 3

    range(1, 4) produces 1, 2 and 3: end value 4 is excluded. Their sum is 6. Do not confuse the written limit with the last visited value.

  4. 4

    An empty list does not execute the for body; total remains 0. Testing emptiness helps find programs that work only with populated examples.

✦
YOUR MISSION

Traverse a list, accumulate a total and interpret the exclusive end of range.

Now it's your turn

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durations = [10, 20, 15]
total = 0
for minutes in durations:
    total = total + minutes
print(total)
Build your answers and check when you are ready.
A moment to understand

Where should the total start when summing the whole list?

I need a hint

The accumulator must remember earlier steps.

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Take it with you

Run the sum with three durations, then an empty list. Make a table showing total before and after each iteration.

PYTHON · .py

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