Python Average Session Duration | Dataford Interview Questions

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Problem

EA SPORTS FC gameplay telemetry contains one record for each completed user session. Write a function that calculates the average session duration across all provided sessions.

Each session is represented by a dictionary containing a user_id, start, and end. The start and end values are integer timestamps measured in minutes from a common reference point. The average should include every session, regardless of whether multiple sessions belong to the same user.

Return 0.0 when the input contains no sessions.

Formal Specification

Implement average_session_duration(sessions).

Input: sessions, a list of dictionaries. Each dictionary has:
- user_id: a string
- start: an integer start timestamp
- end: an integer end timestamp
Output: A floating-point number equal to the mean of end - start for all sessions.

Constraints

0 <= len(sessions) <= 10^5
0 <= start <= end <= 10^9
Every session contains user_id, start, and end
Timestamps are integer minute values

Function Signature

def average_session_duration(sessions):