Level 3Exercise #58

Build a nested index

Index scores by team, then username, without initializing inner dictionaries manually.

What you’ll practice

This Level 3 exercise focuses on nested defaultdict in the Collections curriculum. Solve the challenge prompt above using clear, idiomatic Python and the relevant language or standard-library tools.

Relevant Python reference: collections.defaultdict.

Sample Test Cases

Example #1

Input:score_index([('red','aya',91)])

Output:{'red':{'aya':91}}

Reference Solution

Reveal Reference Solution

def score_index(rows: list[tuple[str, str, int]]):
    from collections import defaultdict
    index = defaultdict(dict)
    for team, user, score in rows:
        index[team][user] = score
    return dict(index)

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Build a nested index

What you’ll practice

Sample Test Cases

Further Reading

Reference Solution