Python: Which practice avoids a common mistake with defaultdict for Grouping?

Difficulty:

Medium

Questions:

1

Time Limit:

2 minutes

Passing Score:

100%

Question

Which practice avoids a common mistake with defaultdict for Grouping?

  1. Ignore the defaultdict for Grouping issue and rely on team discipline instead of clearer APIs or invariants.
  2. Silence the defaultdict for Grouping problem by using broad catches, hidden globals, or extra shared mutable state.
  3. Prefer the version of defaultdict for Grouping that makes behavior less predictable as long as the code still runs.
  4. Do not let automatic key creation hide a bug where a missing key should have been treated as an error instead.

Hint

Look for the option that protects correctness instead of hiding the problem.

Answer and rationale

Correct answer: D. Do not let automatic key creation hide a bug where a missing key should have been treated as an error instead.

Do not let automatic key creation hide a bug where a missing key should have been treated as an error instead. This is a common failure mode in real Python code and a frequent interview follow-up.

Track: Python