Quiz — Lecture 15

Section A from memory, one line each. Section B shows your reasoning - marks are for method, not final answers. Answers are discussed in class; the exit ticket goes on a card.

Section A

A1. When is a mutable default argument created?

A2. What is the standard fix?

A3. Reassigning a parameter vs mutating it: which does the caller see?

A4. is vs ==: what does each test?

Section B

B1. Fix def add_tag(tag, tags=[]) and explain in one sentence.

B2. Predict the output: def f(x, acc=[]): acc.append(x); return acc - called f(1), f(2).

Exit ticket

Answer one of these on your card in 60 seconds (choose any one):

1. When is the complement trick the right tool?

1. Permutations vs combinations in one phrase each.

1. How does simulation back up counting?

Homework

• Before: skim the four student pages; attempt case 1 on paper.
• After: write a five-line pseudocode solution for any case you did not
• Enrichment (optional): the stretch question on each case page.