9. Use heapq for top-N selection

If you only need a few smallest or largest items, avoid sorting the entire collection.

Partial selection algorithms matter when the collection is large and you only care about a small slice of it. heapq expresses that intent directly and avoids paying the readability and runtime cost of a full sort when you do not need one.

9.1. Don’t do this

top_scores = sorted(scores, reverse=True)[:3]

9.2. Do this

from heapq import nlargest

top_scores = nlargest(3, scores)