ray.data.aggregate.AggregateFnV2

class ray.data.aggregate.AggregateFnV2(name: str, zero_factory: Callable[[], AggType], *, on: str | None, ignore_nulls: bool)

Bases: AggregateFn

Provides an interface to implement efficient aggregations to be applied to the dataset.

AggregateFnV2 instances are passed to a Dataset’s .aggregate(...) method to perform aggregations by applying distributed aggregation algorithm:

• aggregate_block is applied to individual blocks, producing partial

  aggregations.

• combine combines new partially aggregated value (previously returned

  from aggregate_block partial aggregations into a singular partial aggregation) with the previously stored accumulator.

• finalize transforms partial aggregation into its final state (for

  some aggregations this is an identity transformation, ie no-op)

PublicAPI (alpha): This API is in alpha and may change before becoming stable.

Methods

aggregate_block	Applies aggregations to individual block (producing partial aggregation results)
combine	Combines new partially aggregated value (previously returned from aggregate_block partial aggregations into a singular partial aggregation) with the previously stored accumulator