ray.data.aggregate.AsList#

class ray.data.aggregate.AsList(on: str, alias_name: str | None = None, ignore_nulls: bool = False)[source]#

Bases: AggregateFnV2[List, List]

Listing aggregation combining all values within the group into a single list element.

Example

# Skip testing b/c this example require proper ordering of the output
# to be robust and not flaky

import ray
from ray.data.aggregate import AsList

ds = ray.data.range(10)
# Schema: {'id': int64}
ds = ds.add_column("group_key", lambda x: x % 3)
# Schema: {'id': int64, 'group_key': int64}

# Listing all elements per group:
result = ds.groupby("group_key").aggregate(AsList(on="id")).take_all()
# result: [{'group_key': 0, 'list(id)': [0, 3, 6, 9]},
#          {'group_key': 1, 'list(id)': [1, 4, 7]},
#          {'group_key': 2, 'list(id)': [2, 5, 8]}

Parameters:

on – The name of the column to collect values from. Must be provided.
alias_name – Optional name for the resulting column.
ignore_nulls – Whether to ignore null values when collecting. If True, nulls are skipped. If False (default), nulls are included in the list.

Methods

`finalize`	Transforms the final accumulated state into the desired output.
`get_agg_name`	Return the agg name (e.g., 'sum', 'mean', 'count').