Method randomize_block_order

python/ray/data/dataset.py:1978–2026

Randomly shuffle the :ref:`blocks ` of this :class:`Dataset`. This method is useful if you :meth:`~Dataset.split` your dataset into shards and want to randomize the data in each shard without performing a full :meth:`~Dataset.random_shuffle`. Exampl

(
        self,
        *,
        seed: Optional[int | RandomSeedConfig] = None,
    )

    @AllToAllAPI
    @PublicAPI(api_group=SSR_API_GROUP)
    def randomize_block_order(
        self,
        *,
        seed: Optional[int | RandomSeedConfig] = None,
    ) -> "Dataset":
        """Randomly shuffle the :ref:`blocks <dataset_concept>` of this :class:`Dataset`.

        This method is useful if you :meth:`~Dataset.split` your dataset into shards and
        want to randomize the data in each shard without performing a full
        :meth:`~Dataset.random_shuffle`.

        Examples:
            >>> import ray
            >>> ds = ray.data.range(100)
            >>> ds.take(5)
            [{'id': 0}, {'id': 1}, {'id': 2}, {'id': 3}, {'id': 4}]
            >>> ds.randomize_block_order().take(5)  # doctest: +SKIP
            {'id': 15}, {'id': 16}, {'id': 17}, {'id': 18}, {'id': 19}]
            >>> ds.randomize_block_order(seed=RandomSeedConfig(seed=42, reseed_after_execution=False)).take(5)  # doctest: +SKIP
            [{'id': 44}, {'id': 45}, {'id': 46}, {'id': 47}, {'id': 80}]
            >>> ds.randomize_block_order(seed=RandomSeedConfig(seed=42, reseed_after_execution=False)).take(5)  # doctest: +SKIP
            [{'id': 44}, {'id': 45}, {'id': 46}, {'id': 47}, {'id': 80}]

            Reproducible but non-deterministic across executions (e.g., training epochs):
            >>> ds = ray.data.range(100)
            >>> ds.randomize_block_order(seed=RandomSeedConfig(seed=42, reseed_after_execution=True)).take(5)  # doctest: +SKIP
            [{'id': 40}, {'id': 41}, {'id': 42}, {'id': 43}, {'id': 28}]
            >>> ds.randomize_block_order(seed=RandomSeedConfig(seed=42, reseed_after_execution=True)).take(5)  # doctest: +SKIP
            [{'id': 92}, {'id': 93}, {'id': 94}, {'id': 95}, {'id': 88}]

        Args:
            seed: An optional random seed. Can be an integer or a :class:`RandomSeedConfig`
                object. If an integer is provided, it defaults to fully deterministic
                behavior (same block order across executions). If None, the block
                order is non-deterministic. See :class:`RandomSeedConfig` for more details on
                seed behavior.

        Returns:
            The block-shuffled :class:`Dataset`.
        """  # noqa: E501

        seed_config = RandomSeedConfig.create_seed_config(seed)

        op = RandomizeBlocks(
            seed_config=seed_config,
            input_dependencies=[self._logical_plan.dag],
        )
        logical_plan = LogicalPlan(op, self.context)
        return Dataset._from_parent(self, logical_plan)

    @PublicAPI(api_group=BT_API_GROUP)
    def random_sample(