Class MaterializedDataset

python/ray/data/dataset.py:7636–7658

A Dataset materialized in Ray memory, e.g., via `.materialize()`. The blocks of a MaterializedDataset object are materialized into Ray object store memory, which means that this class can be shared or iterated over by multiple Ray tasks without re-executing the underlying computations f

@PublicAPI
class MaterializedDataset(Dataset, Generic[T]):
    """A Dataset materialized in Ray memory, e.g., via `.materialize()`.

    The blocks of a MaterializedDataset object are materialized into Ray object store
    memory, which means that this class can be shared or iterated over by multiple Ray
    tasks without re-executing the underlying computations for producing the stream.
    """

    def num_blocks(self) -> int:
        """Return the number of blocks of this :class:`MaterializedDataset`.

        Examples:
            >>> import ray
            >>> ds = ray.data.range(100).repartition(10).materialize()
            >>> ds.num_blocks()
            10

        Time complexity: O(1)

        Returns:
            The number of blocks of this :class:`Dataset`.
        """
        return self._logical_plan.initial_num_blocks()


@PublicAPI(stability="beta")