ray.data.Dataset.count

Dataset.count() → int

Count the number of rows in the dataset.

For Datasets which only read Parquet files (created with read_parquet()), this method reads the file metadata to efficiently count the number of rows without reading in the entire data.

Note

If this dataset consists of more than a read, or if the row count can’t be determined from the metadata provided by the datasource, then this operation will trigger execution of the lazy transformations performed on this dataset.

Examples

>>> import ray
>>> ds = ray.data.range(10)
>>> ds.count()
10

Returns:

The number of records in the dataset.