Extend sequence class with time information

[DriesDeprest]

I would like to extend the Sequence class with start and end time information.

@dataclass
class Sequence:
    sequence_id: int
    team: Team
    start: Time
    end: Time

This way, we can easily retrieve for an event when the sequence it is part of started and ended, which is helpful for my analysis use case.

Thoughts?

[andreasdarsa]

Have you started working on the issue? Because I would be interested in trying this one.

[DriesDeprest]

Hi Andreas,

Apologies for the delay in my response.

No, I haven't started this implementation, feel free to work on it and create a PR :-)

[andreasdarsa]

Thank you. Can you elaborate on the time information you talked about storing in start and end? Is it a certain period (ex. the first half) or a specific point in time?

[DriesDeprest]

The start and end attributes should have Time as their type. This contains both the timestamp and period information. This is used to uniquely describe a point in time in the match.

@dataclass
class Time:
    period: Period
    timestamp: timedelta

[andreasdarsa]

Since in this file we're handling event instances, does the event class have any attribute related to time (both start and end)?

[DriesDeprest]

The Event class has a property time of type Time, which it inherits this from the DataRecord class. This contains both the timestamp and period information. Events don't have a start and end moment. They have a single point in time when they occur. Their time property is used to uniquely describe the point in time during the match on which the event occurred.

Sequences on the other hand, should have a start and end moment, where the start would be equal to the time value of its first event and the end equal to the time value of the last event.

• Definition of the time property, can be seen in the code here: https://github.com/PySport/kloppy/blob/master/kloppy/domain/models/common.py#L1036-L1038

• That the Event class inherits from the DataRecord class, can be seen in the code here:
  https://github.com/PySport/kloppy/blob/master/kloppy/domain/models/event.py#L499

Does that answer your question?

[andreasdarsa]

Yes I think you've pretty much covered what I wanted to clarify. Thank you very much.

[andreasdarsa]

Hi again. I haven't managed to work out anything solid about this issue, so if you have any good ideas, you can take up this one.