ray.data.aggregate.ApproximateTopK.output_field

ApproximateTopK.output_field(input_schema: pyarrow.Schema) → pyarrow.Field | None

Return the PyArrow Field this aggregator produces.

Returns None by default; subclasses that know their output type override. Used by Aggregate.infer_schema() to compute the post-aggregation schema without executing the plan. When any aggregator returns None, the entire Aggregate.infer_schema returns None (callers fall back to a limit(1) execution).