GroupBy.agg

DataFrame agg(AggSpec[] specs...)

Aggregates: one output column per specification (keys first, then aggregations in order). The kernels are the one-slot ArrayData producers, applied per group's row list.

Parameters

specs the aggregation specifications

Returns

the aggregated frame.

Throws

DataFrameException for a missing column, a non-numeric

SUM/MEAN, or duplicate output names.