Appending While Looping, and extend vs append

Why does appending inside `range(len(L))` terminate while appending over L itself loops forever, and how does extend differ from append?

Finger exercises

Short drills on what this video just taught. Write the code, run the checks, and reveal the answer only if you are stuck.

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Exercise 1 of 5

append inside `range(len(L))`

Start from values = [1, 2, 3, 4]. Loop over range(len(values)) and, on each pass, append the loop variable to values. Then assign the final contents of values to final_list.

This loop is safe to run — but try to predict how many passes it makes first.

values = [1, 2, 3, 4]
# your code here — loop over range(len(values)) and append the loop variable
final_list = ...  # the final contents of values

values = [1, 2, 3, 4]
# your code here — loop over range(len(values)) and append the loop variable
final_list = ...  # the final contents of values

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⌘/Ctrl + Enter runs

final_list is a list

the loop ran only over the frozen positions

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Appending While Looping, and extend vs append

append inside range(len(L))

Appending While Looping, and extend vs append

append inside range(len(L))

append inside `range(len(L))`

append inside `range(len(L))`