Clean and Summarize Event Records | Dataford Interview Questions

A data team at Acme Analytics receives raw event records as Python dictionaries. Implement a function that cleans these records and returns a per-user summary suitable for analysis.

Given a list of event dictionaries, process each record as follows:

Ignore records missing user_id, event, or value.
Normalize event by trimming whitespace and converting to lowercase.
Keep only records where normalized event is one of "click", "view", or "purchase".
Convert value to an integer if possible; otherwise ignore the record.
Aggregate valid records by user_id.

For each user, return:

user_id
total_value: sum of valid values
event_counts: counts for each valid event type that appeared

Return the final result as a list of dictionaries sorted by:

total_value descending
user_id ascending

Constraints

1 <= len(records) <= 10^4
Each record is a dictionary with string keys
event may contain extra whitespace or mixed case
value may be an integer or a numeric string
Only click, view, and purchase are valid events

Function Signature

def summarize_records(records):

Problem