Core Collections · interview question

What is the healthiest performance judgment around sorting and grouping?

Multiple choiceMediumchapter-3-curatedpremiumcore-collectionssorting-and-grouping

python

lines = [{"sku": "SKU-2", "qty": 1}, {"sku": "SKU-1", "qty": 4}]
lines.sort(key=lambda row: row["sku"])
print(lines)

Keep sorting and grouping implicit so the script stays short and hope the next engineer infers the rule.Measure before optimizing, then change the part that actually dominates cost instead of guessing from style alone.Delay clarity until production traffic reveals the edge case and then patch it under pressure.Solve the symptom with comments only and avoid changing the code shape around sorting and grouping.

Answer and explanation

Correct answer

B. Measure before optimizing, then change the part that actually dominates cost instead of guessing from style alone.

Why

Premature optimization is usually weaker than targeted optimization backed by measurement.

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What is the healthiest performance judgment around sorting and grouping?

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