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PEAZIT Aha card

The range loop: the stop value is excluded

range(start, stop) produces integers from start inclusive to stop exclusive, normally in steps of one. for assigns each value in turn and runs its indented body.

The range loop: the stop value is excluded

Observation	What it means
range(3)	0, 1, 2
range(2, 5)	2, 3, 4

One worked example

s = 0Prepare a total.
for i in range(1, 4): s = s + iAdd 1, then 2, then 3.
s = 6The upper bound 4 is not added.

Watch out: A third range argument changes the step; negative steps need suitable bounds. break can end a loop early.

Goal, prerequisites and card origin

What you will learn: Count repetitions of a Python for loop.

What you need first: Integers and assignment.

An original PEAZIT working card. Independent expert review and effectiveness testing have not yet taken place. · v1

Reference for the underlying principle ↗

Show connections

Algorithms: order, selection and repetition

Input — supplies initial data — Sequence of steps

Sequence of steps — may contain a decision — Condition

Condition — determines whether to continue — Repetition

Repetition — checks the condition again after a step — Condition

Condition — ends processing when the goal is reached — Output

range(start, stop) produces integers from start inclusive to stop exclusive, normally in steps of one. for assigns each value in turn and runs its indented body.

Without JavaScript, write your answer elsewhere before opening the solution.How many times does for i in range(2, 6) run its body if there is no break? Enter a number.

Solution — open after your own attempt

4 The values are 2, 3, 4, 5: four iterations.

A question for your next return: s starts at 0. In for i in range(3), each iteration runs s = s + 2. What is the final s?

Solution — open after your own attempt

6 Three iterations add two each: 0 + 2 + 2 + 2 = 6.

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