EasyAbout 5 minAggregation & grouping
Count events by type
Given a list of event dicts, return a single dict mapping event_type → number of events of that type.
Order doesn't matter in the output dict. An empty input returns {}.
What the tests check
3 on Run · 4 on Submit01empty input returns empty dict
02counts single-type events
03counts mixed events correctly
Submit runs these and one more check you don’t see, so code written for the visible tests alone can still miss.
Runtime
Python 3.13 in your browser – the standard library plus pandas and numpy; no pip installs.