Summarize Meaningful Data

The previous lesson arranged attempt records into a useful order. A program often needs another view of the same collection: a few facts such as the total, lowest, and highest score.

We could calculate each fact with a loop, but Python already provides focused summary functions for numeric values:

scores = [8, 6, 9]

sum(scores)  # 23
min(scores)  # 6
max(scores)  # 9

Their names state the requested result directly, which keeps the purpose of the calculation visible.

Select meaningful data first

An attempt record contains several numbers:

{
    "score": 8,
    "total": 10,
    "seconds": 75,
}

Do not pass whole dictionaries to numeric summary functions. First collect the field that answers the question:

scores = []
for attempt in attempts:
    scores.append(attempt["score"])

Then summarize scores.

Decide what an empty collection means

sum([]) returns 0, but min([]) and max([]) raise ValueError because there is no smallest or largest item.

Your function’s contract must choose a meaning. For this lesson, an empty attempt list returns:

{
    "total": 0,
    "lowest": None,
    "highest": None,
}

None makes the absence of a lowest or highest score explicit.

The empty list is falsy, so the function can handle it directly:

if not scores:
    return {
        "total": 0,
        "lowest": None,
        "highest": None,
    }

Summarize attempt scores

Build one list of score values. Return total, lowest, and highest, with the documented empty result.