Struct NthValueAccumulator

pub struct NthValueAccumulator { /* private fields */ }

Implementations

impl NthValueAccumulator

pub fn try_new( n: i64, datatype: &DataType, ordering_dtypes: &[DataType], ordering_req: LexOrdering, ) -> Result<Self>

Create a new order-sensitive NTH_VALUE accumulator based on the given item data type.

Trait Implementations

impl Accumulator for NthValueAccumulator

fn update_batch(&mut self, values: &[ArrayRef]) -> Result<()>

Updates its state with the values. Assumes data in the values satisfies the required ordering for the accumulator (across consecutive batches, not just batch-wise).

fn merge_batch(&mut self, states: &[ArrayRef]) -> Result<()>

Updates the accumulator’s state from an Array containing one or more intermediate values.

fn state(&mut self) -> Result<Vec<ScalarValue>>

Returns the intermediate state of the accumulator, consuming the intermediate state.

fn evaluate(&mut self) -> Result<ScalarValue>

Returns the final aggregate value, consuming the internal state.

fn size(&self) -> usize

Returns the allocated size required for this accumulator, in bytes, including Self.

fn retract_batch( &mut self, _values: &[Arc<dyn Array>], ) -> Result<(), DataFusionError>

Retracts (removed) an update (caused by the given inputs) to accumulator’s state.

fn supports_retract_batch(&self) -> bool

Does the accumulator support incrementally updating its value by removing values.

impl Debug for NthValueAccumulator

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.