Core Collections · interview question

Which option is the safer default when shipping code around aggregation patterns?

Multiple choiceHardchapter-3-curatedpremiumcore-collectionsaggregation-patterns

python

orders = [{"region": "US"}, {"region": "EU"}, {"region": "US"}]
counts = {}
for order in orders:
    counts[order["region"]] = counts.get(order["region"], 0) + 1
print(counts)

Choose the simpler shape that keeps the rule obvious, validated, and easy to observe in logs or tests.Keep aggregation patterns implicit so the script stays short and hope the next engineer infers the rule.Solve the symptom with comments only and avoid changing the code shape around aggregation patterns.Delay clarity until production traffic reveals the edge case and then patch it under pressure.

Answer and explanation

Correct answer

A. Choose the simpler shape that keeps the rule obvious, validated, and easy to observe in logs or tests.

Why

The safest default is usually the one that lowers ambiguity and makes errors easier to diagnose.

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Which option is the safer default when shipping code around aggregation patterns?

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