The second assignment: ``python 1 vals = [0, 1, 2] 2 vals[0], vals[1] = vals[1], vals[2] ``

Question

1 vals = [0, 1, 2]
2 vals[0], vals[1] = vals[1], vals[2]

Options

• Aextends the list
• Bdoesn't change the list's length
• Cshortens the list

• A
  12% (8)
• B
  82% (56)
• C
  6% (4)

Explanation

Option B is correct because this line performs simultaneous index assignment - it reassigns existing slots in the list without adding or removing any elements. The right-hand side vals[1], vals[2] is evaluated first as a tuple (1, 2), then unpacked into vals[0] and vals[1], leaving the list as [1, 2, 2] - still three elements.

Option A (extends the list) is wrong because extending requires operations like .append(), .extend(), or += [...]; assigning to an existing index cannot create a new slot.

Option C (shortens the list) is wrong because removing elements requires .pop(), .remove(), del, or slicing reassignment - none of which appear here.

Memory tip: Think of list indices as labeled mailboxes - you can swap what's inside the boxes, but index assignment alone can never add or remove a mailbox.

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