Package io.deephaven.api.agg

Class Count

java.lang.Object

io.deephaven.api.agg.Count

All Implemented Interfaces:

Aggregation

@Immutable
public abstract class Count
extends Object
implements Aggregation

An aggregation that provides a single output column with the number of rows in each aggregation group.

See Also:

• TableOperations.countBy(java.lang.String)

Nested Class Summary

Nested classes/interfaces inherited from interface io.deephaven.api.agg.Aggregation

Aggregation.Visitor

Constructor Summary

Constructors

Constructor	Description
Count()

Method Summary

Modifier and Type	Method	Description
abstract ColumnName	column()
static Count	of(ColumnName name)
static Count	of(String x)
final <V extends Aggregation.Visitor> V	walk(V visitor)	Glue method to deliver this Aggregation to a AggSpec.Visitor.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

Count

public Count()

Method Details

of

public static Count of(ColumnName name)

of

public static Count of(String x)

column

@Parameter
public abstract ColumnName column()

walk

public final <V extends Aggregation.Visitor> V walk(V visitor)

Description copied from interface: Aggregation

Glue method to deliver this Aggregation to a AggSpec.Visitor.

Specified by:

walk in interface Aggregation

Parameters:

visitor - The visitor

Returns:

The visitor