ray.data.expressions.DownloadExpr.to_field

DownloadExpr.to_field(input_schema: pyarrow.Schema) → pyarrow.Field | None

Return the output PyArrow Field given the input schema.

Defaults to pa.field(self.name, self.get_type(input_schema), nullable=self.nullable(input_schema)). Returns None when either the type can’t be resolved or the expression has no name (the latter is invalid for projection list entries; Project enforces this in __post_init__).